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    <title type="text">Terence Eden’s Blog</title>
    <subtitle type="text">Regular nonsense about tech and its effects 🙃</subtitle>
    <updated>2026-10-01T07:47:47Z</updated>
    <rights>© Terence Eden. 🄯 CC BY. See https://shkspr.mobi/blog/copyright-and-copyleft/</rights>
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    <entry>
        <author>
            <name>Terence Eden</name>
            <uri>https://edent.tel/</uri>
        </author>
        <title type="html"><![CDATA[Gadget Review: Una Watch ★★★★☆]]></title>
        <link rel="alternate" type="text/html" href="https://shkspr.mobi/blog/2026/10/gadget-review-una-watch/"/>
        <id>https://shkspr.mobi/blog/?p=76031</id>
        <updated>2026-10-01T07:47:47Z</updated>
        <published>2026-10-02T11:34:48Z</published>
        <category scheme="https://shkspr.mobi/blog" term="gadget"/>
        <category scheme="https://shkspr.mobi/blog" term="review"/>
        <category scheme="https://shkspr.mobi/blog" term="UnaWatch"/>
        <category scheme="https://shkspr.mobi/blog" term="watch"/>
        <summary type="html"><![CDATA[I&#039;ve never been a huge fan of smart watches. My £16 smartwatch is basically fine, but the OS is closed source and there&#039;s no way to add new functionality.  Previously I had the eInk Watchy which was a pain to use and really poorly designed.  Even back in 2014 I was bemoaning the design compromises in the MyKronoz ZeWatch Smart Watch.  So why did I pick up the Una Watch?  Firstly, the Una Watch is …]]></summary>
        <content type="html" xml:base="https://shkspr.mobi/blog/2026/10/gadget-review-una-watch/"><![CDATA[<p>I've never been a huge fan of smart watches. My <a href="https://shkspr.mobi/blog/2025/08/i-bought-a-16-smartwatch-just-because-it-used-usb-c/">£16 smartwatch</a> is basically fine, but the OS is closed source and there's no way to add new functionality.  Previously I had the <a href="https://shkspr.mobi/blog/2023/06/review-watchy-an-eink-watch-full-of-interesting-compromises/">eInk Watchy</a> which was a pain to use and really poorly designed.  Even back in 2014 I was bemoaning the design compromises in the <a href="https://shkspr.mobi/blog/2014/11/disassembling-the-mykronoz-zewatch-smart-watch/">MyKronoz ZeWatch Smart Watch</a>.</p>

<p>So why did I pick up the Una Watch?</p>

<p>Firstly, the Una Watch is designed in Scotland <del>from girders</del>, and it's always nice to support local businesses.</p>

<p>Secondly, as a <a href="https://shkspr.mobi/blog/2026/07/im-a-usb-c-maximalist/">USB-C Maximalist</a> I want gadgets which can plug in to the same cables as all my other toys. No magnetic pucks here!</p>

<p>Thirdly, it is (almost) <a href="https://unawatch.com/pages/open-source">completely open source</a>.</p>

<p>Finally, it is repairable. You can easily unscrew it to replace the components. As my cheap smartwatch's dial has died after 12 months of use, that's a pretty compelling proposition!</p>

<p>Let's put it through its paces!</p>

<h2 id="first-impressions"><a href="https://shkspr.mobi/blog/2026/10/gadget-review-una-watch/#first-impressions">First Impressions</a></h2>

<p>I bought mine second hand (yay for sustainability) and it arrived with a flat battery. The first charge from 0-100% took a little over an hour. My USB-C power monitor showed it taking in about 5V and 0.17 amps.</p>

<img src="https://shkspr.mobi/blog/wp-content/uploads/2026/09/Charging.webp" alt="Power monitor showing 0.84W." width="1024" height="576" class="aligncenter">

<p>It happily charged from a PD plug, but didn't get any faster than about 0.84W. Basically, I can fully charge it on most public transport in London.</p>

<p>The time seemed accurate, there were options to play about with, the vibrations for notifications were easy to feel. There is an option to make it beep with every button press - I turned that off sharpish!</p>

<h2 id="disclaimer"><a href="https://shkspr.mobi/blog/2026/10/gadget-review-una-watch/#disclaimer">Disclaimer</a></h2>

<p>I am <em>not</em> <a href="https://shkspr.mobi/blog/2026/09/are-you-a-smartwatch-power-user/">a smartwatch power user</a>. I'm not using this to minutely track all my exercise or calculate if my heart is going to explode.  I don't need cm level precision of my GPS. I didn't sync this with Strava or anything else.</p>

<h2 id="apps"><a href="https://shkspr.mobi/blog/2026/10/gadget-review-una-watch/#apps">Apps</a></h2>

<p>The official Android app (which, sadly, isn't Open Source) worked fine on GrapheneOS. It found the watch, updated its GPS almanac, and let me browse the app store &amp; install apps. Obviously early days, but there are a variety of community developed apps to play with.</p>

<img src="https://shkspr.mobi/blog/wp-content/uploads/2026/09/apps.webp" alt="List of apps." width="504" height="728" class="aligncenter">

<p>Annoyingly the watch needs to be restarted after every app is installed - but that only take a handful of seconds.</p>

<img src="https://shkspr.mobi/blog/wp-content/uploads/2026/09/Restart-watch.webp" alt="Message telling me the watch needs to restart." width="504" height="640" class="aligncenter">

<p>There are some <em>strange</em> error messages.</p>

<img src="https://shkspr.mobi/blog/wp-content/uploads/2026/09/error-message.webp" alt="birthday must be a valid ISO 8601 date string country must be a valid ISO31661 Alpha2 code." width="504" height="426" class="aligncenter">

<p>That isn't the sort of message which should be shown to users.</p>

<p>But, on the plus side, you can install Doom!</p>

<img src="https://shkspr.mobi/blog/wp-content/uploads/2026/09/Doom.webp" alt="App store listing showing Doom on the watch." width="504" height="550" class="aligncenter">

<h2 id="the-screen"><a href="https://shkspr.mobi/blog/2026/10/gadget-review-una-watch/#the-screen">The Screen</a></h2>

<p>Oddly for a modern smartwatch, the screen stays on <em>all the time!</em> But this isn't some power-hungry OLED, nor is it static eInk. Instead it is a <a href="https://www.andersdx.com/memory-in-pixel-displays/">memory in pixel</a> display - black background with orange, blue, and white pixels.  The backlight remains off most of the time and is easy enough to see in daylight. It is <em>slightly</em> reflective - but not too bad.</p>

<img src="https://shkspr.mobi/blog/wp-content/uploads/2026/09/Reflective.webp" alt="Watch showing notifications, there is a bit of a reflection." width="1024" height="576" class="aligncenter">

<p>Note the <code>??</code> on the notifications - more on that later.</p>

<p>Annoyingly, there's no "raise wrist to light" option. You have to interact with the watch to get the screen on. The accelerometer should allow this functionality - so perhaps it just needs to be activated in the firmware? It is bright enough to see in the dark, but not so bright it will dazzle you or people nearby.</p>

<p>There's no touchscreen - instead there are four buttons around the face. Up, down, select, back. I did find myself repeatedly jabbing at the screen to no avail.</p>

<p>So, to light it, press the back button or hold one of the other buttons.</p>

<p>The colour scheme is pleasant enough. I miss having a full colour display so I can see a photo of my wife whenever I glance at the screen. But the low power usage can't be argued with.</p>

<h2 id="notifications"><a href="https://shkspr.mobi/blog/2026/10/gadget-review-una-watch/#notifications">Notifications</a></h2>

<p>I couldn't get notifications working at first. The app just refused to let me toggle them on. Eventually I found an app in the app-store which claimed to enable them. That didn't work either.</p>

<p>Unpairing, repairing, and reinstalling the app made them spring to life.</p>

<p>There's no notification history. Once you've clicked to read it, that's it. Gone forever. Considering this has 4GB storage, that's an odd decision.</p>

<p>Some of the notifications were slightly corrupt - showing question marks in place of (I assume) esoteric Unicode.</p>

<img src="https://shkspr.mobi/blog/wp-content/uploads/2026/09/Question-Mark-notification.webp" alt="A notification on screen with a question mark before the user's name." width="1024" height="768" class="aligncenter">

<p>There's no way to customise the vibrate pattern - so everything "feels" the same on your wrist.</p>

<p>At the moment, the Una Watch sends <em>every</em> notification to your phone. You can't tell it to ignore certain WhatsApp groups, or only allow text messages from your spouse.  The only way to get fine-grained notifications is with a third-party app like…</p>

<h2 id="gadgetbridge"><a href="https://shkspr.mobi/blog/2026/10/gadget-review-una-watch/#gadgetbridge">Gadgetbridge</a></h2>

<p>You're not tied to the official app. <a href="https://gadgetbridge.org/gadgets/wearables/una/">Gadgetbridge support is excellent</a>. There are a few things missing (you can't install apps or set alarms) - but if you want to measure your heart rate, send notifications, etc you'll be fine.</p>

<h2 id="linux-compatibility"><a href="https://shkspr.mobi/blog/2026/10/gadget-review-una-watch/#linux-compatibility">Linux Compatibility</a></h2>

<p>The Una Watch plugs in to USB-C and shows up as 3.5GB of exFAT formatted storage.</p>

<img src="https://shkspr.mobi/blog/wp-content/uploads/2026/10/Una-Filesystem.webp" alt="Filesystem view showing various JSON files." width="500" height="649" class="aligncenter">

<p>You can manually edit the JSON files if you like. I think you can copy off your workout data. Or you can just use it as portable storage.</p>

<p>Under <code>lsusb</code> it describes itself as <code>0483:52a4 STMicroelectronics UNA Watch</code></p>

<h2 id="battery-life"><a href="https://shkspr.mobi/blog/2026/10/gadget-review-una-watch/#battery-life">Battery Life</a></h2>

<p>After a full day of use the battery was at around 95% - that was with a bit of GPS, several notifications, heart rate monitoring, step counting, and a bunch of fiddling. With more GPS use, that's going to be heavier on the battery.</p>

<p>But the joy of USB-C is that I can thwack in the same cable as I use for all my other gadgets. I can even plug it into my phone and leach a bit of power from there.</p>

<h2 id="development"><a href="https://shkspr.mobi/blog/2026/10/gadget-review-una-watch/#development">Development</a></h2>

<p>The watch comes will a full <a href="https://github.com/UNAWatch/una-sdk">Open Source SDK</a> including lots of assets. There are several tutorials and a friendly community board.</p>

<p>Of course, everything has to be done in C++ - an accurs'd language which I learned in the last century and wish I'd forgotten.</p>

<p>Annoyingly, the <a href="https://github.com/UNAWatch/una-sdk/blob/main/Docs/sdk-setup.md">TouchGFX GUI designer</a> only works in Windows.</p>

<p>I'm going to try to build my own watch faces and a few niche apps.</p>

<h2 id="downsides"><a href="https://shkspr.mobi/blog/2026/10/gadget-review-una-watch/#downsides">Downsides</a></h2>

<p>There are a few things this watch <em>doesn't</em> do - some of these may be deal-breakers for you, but weren't for me.</p>

<ul>
<li>No payments. There's no tap-to-pay, NFC, or anything like that.</li>
<li>No microphone. You cannot speak into your Una Watch or take calls on it.</li>
<li>No speaker. There's a little buzzer which can make squeaks and squawks - but you won't be playing your music through it.</li>
<li>While the apps and SDK are fully open, the firmware isn't (yet).</li>
<li>Can't reply to notifications.</li>
<li>No maps or directions (yet).</li>
<li>Step counter only shows the full day - no hour-by-hour view.</li>
</ul>

<p>Some of these things can and will be fixed in software. Others are limitations of the hardware.</p>

<h2 id="final-thoughts"><a href="https://shkspr.mobi/blog/2026/10/gadget-review-una-watch/#final-thoughts">Final Thoughts</a></h2>

<p>The Una Watch has dropped in price to £180. I grabbed mine 2nd hand from eBay for £120. At either price, it's decent value <em>if</em> you're happy to play with alpha / beta quality technology.</p>

<p>If you're a serious athlete, you'll probably want a more expensive and polished experience. If you are tied into the Apple or Google ecosystems, you'll probably want one of their watches.</p>

<p>If you like tinkering, want to experiment with new technology, or simply want to support a British company trying to build something open - then this is the watch for you. Yes, there are some rough edges, but I fundamentally believe that technology should be Open Source, repairable, and give control to its users.</p>
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    </entry>
    <entry>
        <author>
            <name>Terence Eden</name>
            <uri>https://edent.tel/</uri>
        </author>
        <title type="html"><![CDATA[Are you a smartwatch "power user"?]]></title>
        <link rel="alternate" type="text/html" href="https://shkspr.mobi/blog/2026/09/are-you-a-smartwatch-power-user/"/>
        <id>https://shkspr.mobi/blog/?p=74267</id>
        <updated>2026-09-28T09:40:08Z</updated>
        <published>2026-09-30T11:34:26Z</published>
        <category scheme="https://shkspr.mobi/blog" term="android"/>
        <category scheme="https://shkspr.mobi/blog" term="gadgets"/>
        <category scheme="https://shkspr.mobi/blog" term="usability"/>
        <category scheme="https://shkspr.mobi/blog" term="watch"/>
        <summary type="html"><![CDATA[What do you use your smartwatch for?  A few weeks ago, I overheard a conversation between someone on the Pixel Watch team and a woman I know. He was quizzing her at a party about her Pixel watch and what features she used. He&#039;d ignored me when I said I had a non-Google watch.  She thought for a moment and said, other than telling the time, all she used were pretty much the step counter and…]]></summary>
        <content type="html" xml:base="https://shkspr.mobi/blog/2026/09/are-you-a-smartwatch-power-user/"><![CDATA[<p>What do you use your smartwatch for?</p>

<p>A few weeks ago, I overheard a conversation between someone on the Pixel Watch team and a woman I know. He was quizzing her at a party about her Pixel watch and what features she used. He'd ignored me when I said I had <a href="https://shkspr.mobi/blog/2025/08/i-bought-a-16-smartwatch-just-because-it-used-usb-c/">a non-Google watch</a>.  She thought for a moment and said, other than telling the time, all she used were pretty much the step counter and contactless payments. He looked a bit crestfallen at his impromptu user-research participant and somewhat dismissively sneered, "Well, you're not exactly a power user, are you?"</p>

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Honestly, this guy was *such* an arse. Really spoiled an otherwise lovely party. Like, I don't mind talking about people's work - but it seemed that was the only thing he was interested in talking about. He also seemed genuinely offended that I'd bought a non-Google watch and didn't want to hear why I liked it. Oh well, his loss!

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<p>I'm trying to imagine what being a "power user" of a watch is like. Can anyone enlighten me?</p>

<p>I think smart-watches are much like Alexa. What the user <em>wants</em> to do with it is almost totally at odds with what the company is selling. Alexæ are mostly kitchen timers, song players, and light switches. No one is a "power user" constantly installing skills and using it for anything which increases the product team's engagement metrics.</p>

<p>The same is probably true of watches. Alerts are nifty - but cumbersome for replies. The health stuff is useful - but only for a subset of users. Seeing the time is great - but if the battery lasts less than a week, who wants to keep that screen on?</p>

<p>People use watches because they are moderately more convenient to carry than the giant phones we have nowadays.</p>

<p>Back when mobile phones were new, exciting, and made a feature of being tiny, I was working for a network operator and trying to come up with reasons for people to use our brand-new 3G network. All the research we had showed that people used their phones for exactly three things:</p>

<ol>
<li>Voice calls</li>
<li>Text messages</li>
<li>A third thing</li>
</ol>

<p>That "3rd thing" was varied. For some it was playing snake, for others it was a calendar, and a few took photos. But almost no-one used their phone beyond the basics. They weren't investigating the sub-menus, nor were they using most of their device's capability unless it was heavily advertised to them (ringtones, basically).</p>

<p>It took the industry a <em>huge</em> amount of effort to get people to actually use their phones for more than calls and texts. Part of that was bigger screens with enticing icons (<a href="https://shkspr.mobi/blog/2012/04/give-customers-an-elevator-pitch-for-your-app/">although users will always be reluctant to click mysterious icons</a>). Another part was that phones became genuinely useful. But perhaps the biggest change, I think, is that phones became <em>easy to use</em>.</p>

<p>Watches have tiny screens. You can only get a few words of a message on there. Icons are tiny and hard to reliably tap. Swiping away at your wrist or fiddling with a crown is a faff. Talking into your wrist makes you look like a prat. Interacting with a smartwatch is <strong>annoying</strong>. Why would anyone want to spend more time using it than is strictly necessary?</p>

<p>I'm sure there are some people out there browsing the web on their wrist, and sending endless voice-notes to their AI assistant, and setting up complex travel plans by tapping their nose on the screen, and installing new watch faces which always point to the nearest Dignitas clinic, and seeing what their heart-rate did during that last run, and tracking whether their menstrual cycle is synced to the phases of the moon, and hoping that tripping on the stairs didn't send an alert to the emergency services, and whatever else the team has cooked up to show that they're still innovating.</p>

<p>But I'll bet those "power users" are vastly outnumbered by people who are using a smartwatch for the limited set of actions which are useful to them; not to the manufacturer.</p>

<p>Perhaps the real power users have is the power to use a device on their own terms?</p>
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    </entry>
    <entry>
        <author>
            <name>Terence Eden</name>
            <uri>https://edent.tel/</uri>
        </author>
        <title type="html"><![CDATA[Book Review: Bobiverse Books 1-3 by Dennis E. Taylor ★★★☆☆]]></title>
        <link rel="alternate" type="text/html" href="https://shkspr.mobi/blog/2026/09/book-review-bobiverse-books-1-3-by-dennis-e-taylor/"/>
        <id>https://shkspr.mobi/blog/?p=73671</id>
        <updated>2026-09-26T12:28:34Z</updated>
        <published>2026-09-28T11:34:52Z</published>
        <category scheme="https://shkspr.mobi/blog" term="Book Review"/>
        <category scheme="https://shkspr.mobi/blog" term="Sci Fi"/>
        <summary type="html"><![CDATA[Like sticky popcorn, this is a moreish but ultimately unsatisfying set of stories. After I flamed out of Dungeon Crawler Carl, someone suggested I try this series. I can see why! It&#039;s campy sci-fi fun, with enough tropes to keep you chuckling and enough tension to keep you turning the pages.    Bob&#039;s brain is uploaded to a computer post-mortem. Awoken in a dystopian future, he has to pilot a…]]></summary>
        <content type="html" xml:base="https://shkspr.mobi/blog/2026/09/book-review-bobiverse-books-1-3-by-dennis-e-taylor/"><![CDATA[<img src="https://shkspr.mobi/blog/wp-content/uploads/2026/08/bobiverse.webp" alt="Book covers for the Bobiverse series." width="275" height="225" class="alignleft size-full wp-image-73672">

<p>Like sticky popcorn, this is a moreish but ultimately unsatisfying set of stories. After I flamed out of <a href="https://shkspr.mobi/blog/2026/07/book-review-dungeon-crawler-carl-by-matt-dinniman/">Dungeon Crawler Carl</a>, someone suggested I try this series. I can see why! It's campy sci-fi fun, with enough tropes to keep you chuckling and enough tension to keep you turning the pages.</p>

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I kinda hate how quickly I devoured these books. They're sort of like a bowl of bland potato snacks which, nevertheless, you find yourself emptying into your gullet. There are so many *good* sci-fi books that I have no idea why I fixated on these? 

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<p>Bob's brain is uploaded to a computer post-mortem. Awoken in a dystopian future, he has to pilot a spaceship to strange new worlds, put right what once went wrong, and hoping The Force will be with him, always. Oh, and he repeatedly clones himself. Creating a universe populated with Bobs (a "Bobiverse" if you will)</p>

<p>It's your standard "only I, a slightly geeky guy with lots of pop-culture knowledge, can save the world" fare which is beloved by slightly geeky guys everywhere who think they're smarter than all those normies just because they can recite the list of Hugo winners alphabetically.</p>

<p>Like <a href="https://shkspr.mobi/blog/2015/09/what-i-read-on-my-holidays/">Ready Player One</a> it throws in as many quips and catchphrases as the plot will bear. Unlike Cline's work, it never really commits to them, so you end up with a scattering of Monty Python, Star Wars, and the X-Files without an overall theme developing.</p>

<p>And, in keeping with Andy Weir's The Martian, it's all just one guy sciencing the shit out of the problem. Except that lots of the science is sort of hand-waved away with "and then I 3D printed a thing".</p>

<p>Similar to both those books is an almost total lack of female characters. The ones that are in the first two are either plot-points or harridans. By the third there's a love interest who is <em>slightly</em> more rounded, and a couple of other incidentals, but offset against yet another woman who just can't appreciate the "genius" of Bob.</p>

<p>It's all good page turning fun other than the fact that Bob is a <em>total</em> cretin. He begins a slow descent into fascist dictator and barely even comments on it. He spies, carries out extra-judicial killings, and meddles in politics to his own advantage. At no point does the text ever really engage with the fact that <strong>Bob is a monster</strong>.</p>

<p>The character rarely reflects on whether his behaviour meets the moral standard he expects of others. He bemoans the aliens who are destroying entire ecosystems while simultaneously wiping out whole species himself. At times he is a conniving bully and reacts badly to anyone who pushes back against the ineffable will of Bob.</p>

<p>The jumping back-and-forth between the different Bobs is a bit frustrating, a bit like flicking between TV channels. I wish each story strand were allowed some space to develop - but instead it's one chapter of this planet, then one chapter of another, before (eventually) circling back.</p>

<p>Annoyingly, <a href="http://dennisetaylor.org/wheres-the-whatever-version/#WhereEpub">the books are only available on Amazon Kindle</a>. They're not on any other platform or library. I'm grateful to the friend who lent me their copies. I binged the first three but, without any indication that Bob will mature as a character or face a reckoning for his egregious actions, that's where I stopped.</p>
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        <thr:total>2</thr:total>
    </entry>
    <entry>
        <author>
            <name>Terence Eden</name>
            <uri>https://edent.tel/</uri>
        </author>
        <title type="html"><![CDATA[Gig Review: Public Service Broadcasting's Race For Space at Alexandra Palace ★★★★⯪]]></title>
        <link rel="alternate" type="text/html" href="https://shkspr.mobi/blog/2026/09/gig-review-public-service-broadcastings-race-for-space-at-alexandra-palace/"/>
        <id>https://shkspr.mobi/blog/?p=75993</id>
        <updated>2026-09-27T09:05:44Z</updated>
        <published>2026-09-27T11:34:08Z</published>
        <category scheme="https://shkspr.mobi/blog" term="gig"/>
        <category scheme="https://shkspr.mobi/blog" term="review"/>
        <summary type="html"><![CDATA[Ahhh! PSB&#039;s RFS! A delightfully indulgent soundscape of melodic wonder, performed here on its 10th (ish) anniversary. Is it really nostalgia if an album is only a decade old? It feels like it has been in the air forever.    For something which is seemingly made up of samples, it would have been easy for them to half-arse it and basically just play the CD. Instead we got a full band, guest…]]></summary>
        <content type="html" xml:base="https://shkspr.mobi/blog/2026/09/gig-review-public-service-broadcastings-race-for-space-at-alexandra-palace/"><![CDATA[<p>Ahhh! PSB's RFS! A delightfully indulgent soundscape of melodic wonder, performed here on its 10th (ish) anniversary. Is it really nostalgia if an album is only a decade old? It feels like it has been in the air forever.</p>

<img src="https://shkspr.mobi/blog/wp-content/uploads/2026/09/On-Stage.webp" alt="The band on stage with giant projections behind them." width="2048" height="1542" class="aligncenter">

<p>For something which is seemingly made up of samples, it would have been easy for them to half-arse it and basically just play the CD. Instead we got a full band, guest singers, and 360° video projection,</p>

<img src="https://shkspr.mobi/blog/wp-content/uploads/2026/09/Laser-Display.webp" alt="Flight controls projected above the audience." width="2048" height="1152" class="aligncenter">

<p>Oh, also a disco Sputnik flying over the crowd!</p>

<img src="https://shkspr.mobi/blog/wp-content/uploads/2026/09/Disco-Sputnik.webp" alt="A large model Sputnik covered in lights." width="2048" height="1152" class="aligncenter">

<p>Simply magical! As were the indoor fireworks.</p>

<img src="https://shkspr.mobi/blog/wp-content/uploads/2026/09/Fireworks.webp" alt="Sparks shooting upwards from the stage." width="2048" height="1152" class="aligncenter">

<p>I might quibble a little with their song choices (no Gagarin!) but hearing the crowd repeatedly scream "GO!" was magnificent.</p>

<p>Ally Pally isn't a raked venue, so the video projection of the band was most welcome. An excellent gig in a splendid location.</p>

<h2 id="pre-show-and-post-show"><a href="https://shkspr.mobi/blog/2026/09/gig-review-public-service-broadcastings-race-for-space-at-alexandra-palace/#pre-show-and-post-show">Pre-show and Post-show</a></h2>

<p>As I've written about before, <a href="https://shkspr.mobi/blog/2024/12/the-art-of-the-pre-show-and-post-show/">the art of the Pre-Show and Post-Show</a> is vital for getting people to pay for events outside of their homes. Right now I can stream all the music in the world for a year for about the same price as a couple of gig tickets.  Why should I freeze my arse off outside, paying stupid money for mass-produced lager, when I could be at home?</p>

<p>PSB kept up a constant stream of emails talking about the gig. Not an overwhelming amount, just letting people peek behind the curtain of organising it, giving helpful information about logistics, and letting us know about merchandise which was available.</p>

<p>Crucially, they also gave us stage timings for them and their support act! How many times have you turned up on time to a gig only to spend an hour listening to some crap DJ before the crew even started setting up the stage? PSB treat their fans with respect.</p>

<p>Ally Pally isn't a venue I've been to before. It was well laid out with decent toilet provision - including a big block of portaloos at the back of the hall. The beer prices weren't ruinous, but I kind of resented paying £15 for a veggie hotdog and a handful of chips.</p>

<p>Some venues seem to think that screaming at punters to open their bags will make for an enjoyable visit. Here the security staff were polite and not overly officious. Water bottles were allowed in with a cheery wave.</p>

<p>Post show - although the train stations are downhill, there were several buses waiting to take punters directly back. That's a perfect way of treating guests at your venue - ensuring that they get home safe and sound.</p>
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        <thr:total>7</thr:total>
    </entry>
    <entry>
        <author>
            <name>Terence Eden</name>
            <uri>https://edent.tel/</uri>
        </author>
        <title type="html"><![CDATA[No errors, no warnings, no gods, no masters - HTML Purity is a Fetish]]></title>
        <link rel="alternate" type="text/html" href="https://shkspr.mobi/blog/2026/09/no-errors-no-warnings-no-gods-no-masters-html-purity-is-a-fetish/"/>
        <id>https://shkspr.mobi/blog/?p=74960</id>
        <updated>2026-09-26T12:24:48Z</updated>
        <published>2026-09-26T11:34:02Z</published>
        <category scheme="https://shkspr.mobi/blog" term="HTML"/>
        <category scheme="https://shkspr.mobi/blog" term="webdev"/>
        <summary type="html"><![CDATA[&#34;The problem with defending the purity of the HyperText Markup Language is that HTML is about as pure as a cribhouse whore. The standard doesn&#039;t just borrow concepts from better languages; on occasion, HTML has pursued other programming languages down alleyways to beat them unconscious and rifle their pockets for new syntax.&#34;    Englitch is an pretty goode langwidge. even you no grok all the…]]></summary>
        <content type="html" xml:base="https://shkspr.mobi/blog/2026/09/no-errors-no-warnings-no-gods-no-masters-html-purity-is-a-fetish/"><![CDATA[<p>"The problem with defending the purity of the HyperText Markup Language is that HTML is about as pure as a cribhouse whore. The standard doesn't just borrow concepts from better languages; on occasion, HTML has pursued other programming languages down alleyways to beat them unconscious and rifle their pockets for new syntax<sup id="fnref:soz"><a href="https://shkspr.mobi/blog/2026/09/no-errors-no-warnings-no-gods-no-masters-html-purity-is-a-fetish/#fn:soz" class="footnote-ref" title="With the appropriate amount of apologies to James Nicoll" role="doc-noteref">0</a></sup>."</p>

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Am I being too harsh in calling technical purity a fetish? I don't think so. But I guess I would say that wouldn't I? My Kink *Is* My Kink And That's OK.

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<p>Englitch is an pretty goode langwidge. even you no grok all the pacific bits you got the jist &amp; the splelling &amp; grandma dont mattr to much.</p>

<p>HTML is much the same. You can write utterly malformed, derranged, non-standards complaint HTML and most browsers will just say "Yeah, sure, whatever dawg!" and render it adequately. Take a look at the source code for <a href="https://www.todepond.com/">TodePond</a> - a lovely website but some of the most abused HTML I've seen.</p>

<p>There's a brilliant blog post by Jens Oliver Meiert which looks at whether HTML validity is seen as a priority for major sites. Basically, no.</p>

<blockquote><p>It’s time for the annual analysis of how much of the HTML code in the field is error-free and valid. The short version: 1% of the most-frequented sites on this planet uses valid HTML—and 99% don’t.</p>

<p><a href="https://meiert.com/blog/html-conformance-2026/">2 of the Global Top 200 Websites Use Valid HTML</a></p></blockquote>

<p>iS ThAt A pRoBlEm????</p>

<p>My site is proudly HTML Valid. Run it through the <a href="https://validator.w3.org/nu/?doc=https%3A%2F%2Fshkspr.mobi%2Fblog%2F">HTML Validator</a> or the <a href="https://validator.schema.org/#url=https%3A%2F%2Fshkspr.mobi%2Fblog">Schema.org Validator</a> and you'll see that it is <em>fucking perfect!</em> Same with my <a href="https://validator.w3.org/feed/check.cgi?url=https%3A%2F%2Fshkspr.mobi%2Fblog%2Ffeed">RSS Feed</a> and <a href="https://validator.w3.org/feed/check.cgi?url=https%3A%2F%2Fshkspr.mobi%2Fblog%2Ffeed%2Fatom">Atom Feed</a>. Not so much as an advisory bit of info, a couched warning, or a sternly worded suggestion<sup id="fnref:4now"><a href="https://shkspr.mobi/blog/2026/09/no-errors-no-warnings-no-gods-no-masters-html-purity-is-a-fetish/#fn:4now" class="footnote-ref" title="At the time of writing. Who knows what batshit bugs I'll accidentally include in the future 🙃" role="doc-noteref">1</a></sup>.</p>

<p>Every last bit pure and holy.</p>

<p>Of course, syntactically valid HTML is neither necessary nor sufficient for any purpose.</p>

<p>Perfect HTML doesn't imply that a site is accessible (although, I'm proud to say mine meets or exceeds all WCAG guidance<sup id="fnref:wcag"><a href="https://shkspr.mobi/blog/2026/09/no-errors-no-warnings-no-gods-no-masters-html-purity-is-a-fetish/#fn:wcag" class="footnote-ref" title="Again, it is possible to make something pass automated testing while still being an accessibility mess." role="doc-noteref">2</a></sup>).</p>

<p>Perfect HTML doesn't guarantee that the information it contains is accurate<sup id="fnref:purrrrrfect"><a href="https://shkspr.mobi/blog/2026/09/no-errors-no-warnings-no-gods-no-masters-html-purity-is-a-fetish/#fn:purrrrrfect" class="footnote-ref" title="Although, of course, everything you read in this site is 100% accurate." role="doc-noteref">3</a></sup>.</p>

<p>Perfect HTML, at best, merely <em>implies</em> that the author gives a damn about such things. Much like <a href="https://knolling.org/">Knolling</a>, it leaves a suggestion that order is preferable to chaos<sup id="fnref:knoll"><a href="https://shkspr.mobi/blog/2026/09/no-errors-no-warnings-no-gods-no-masters-html-purity-is-a-fetish/#fn:knoll" class="footnote-ref" title="Or some horrifying psychological issue. Potato / Tomato." role="doc-noteref">4</a></sup>.</p>

<p>It is said that one of the reasons HTML succeeded is that it is lax about validation. Most programming languages will shit the bed if you dare to leave out so much as a single semicolon. The compiler wails can be heard throughout the land.</p>

<p>By contrast, HTML is designed to be sympathetic to the frailty of the human mind. "Oh, you didn't close an element? Well, you opened a new one which I guess implies the same thing. Did you forget the correct syntax? Never mind - it'll be our little secret."</p>

<p>That's why <a href="https://shkspr.mobi/blog/2025/12/the-web-runs-on-tolerance/">XHTML failed</a> - the browser would literally refuse to render a page if it didn't meet the spec. Who can be bothered with that?! HTML just lets you get on with things.</p>

<p>As I've mentioned before, <a href="https://shkspr.mobi/blog/2020/05/postels-law-also-applies-to-human-communication/">humans don't write or speak in Backus–Naur form</a>. Our ideas are loosely expressed in a floating grammar which lends itself to paradoxical impossibilities and logical tautologies. And yet most of us can still parse <a href="https://en.wikipedia.org/wiki/Garden-path_sentence">weird sentences</a> without too much effort.</p>

<p>But most computer languages are different. It might be obvious to you that <code>if (x = 42)</code> means "compare the value of x to 42" - but what the computer sees is "if assign x the value of 42". Within computing our code needs to be <em>rigorously formal</em> and any syntax errors will lead to show-stopping bugs.</p>

<p>Imagine if every time a human wrote <a href="https://en.wikipedia.org/wiki/Romani_ite_domum"><i lang="la">Romanes eunt domus</i></a> the world simply crashed. It would be intolerable.</p>

<p>HTML is more like a human language than a computing language. You can understand human speech over a crackly phone line in a foreign accent - Web Browsers understand CP-1252 encoded text with bizarre syntax errors.</p>

<p>If it is OK to write bad HTML, why do some of us fetishise "pure" HTML?</p>

<p>I think it comes down to an ingrained belief that it is polite to reduce ambiguity. It is nice to be precise<sup id="fnref:100"><a href="https://shkspr.mobi/blog/2026/09/no-errors-no-warnings-no-gods-no-masters-html-purity-is-a-fetish/#fn:100" class="footnote-ref" title="I will grant you, there's also a strain of 100% Completionist which compels me to get &quot;top score&quot; on all the benchmarks. But that's just pure vanity." role="doc-noteref">5</a></sup>. It reduces the cognitive burden on anyone (or anything) which reads what we have written. We are holding up our end of the social contract by producing something unadulterated and easy to comprehend. It reduces the likelihood of different browsers rendering things differently but, almost on a cellular level, we <em>feel</em> that <strong>things must be done properly</strong>.</p>

<p>The browser doesn't care about your inability to follow standards. But you should have some fucking self-respect and do it anyway.</p>

<div id="footnotes" role="doc-endnotes">
<hr aria-label="Footnotes">
<ol start="0">

<li id="fn:soz">
<p>With the appropriate amount of apologies to <a href="https://en.wikiquote.org/wiki/James_Nicoll">James Nicoll</a>&nbsp;<a href="https://shkspr.mobi/blog/2026/09/no-errors-no-warnings-no-gods-no-masters-html-purity-is-a-fetish/#fnref:soz" class="footnote-backref" role="doc-backlink">↩︎</a></p>
</li>

<li id="fn:4now">
<p>At the time of writing. Who knows what batshit bugs I'll accidentally include in the future 🙃&nbsp;<a href="https://shkspr.mobi/blog/2026/09/no-errors-no-warnings-no-gods-no-masters-html-purity-is-a-fetish/#fnref:4now" class="footnote-backref" role="doc-backlink">↩︎</a></p>
</li>

<li id="fn:wcag">
<p>Again, it is possible to make something <a href="https://www.matuzo.at/blog/building-the-most-inaccessible-site-possible-with-a-perfect-lighthouse-score/">pass automated testing while still being an accessibility mess</a>.&nbsp;<a href="https://shkspr.mobi/blog/2026/09/no-errors-no-warnings-no-gods-no-masters-html-purity-is-a-fetish/#fnref:wcag" class="footnote-backref" role="doc-backlink">↩︎</a></p>
</li>

<li id="fn:purrrrrfect">
<p>Although, of course, everything you read in this site is 100% accurate.&nbsp;<a href="https://shkspr.mobi/blog/2026/09/no-errors-no-warnings-no-gods-no-masters-html-purity-is-a-fetish/#fnref:purrrrrfect" class="footnote-backref" role="doc-backlink">↩︎</a></p>
</li>

<li id="fn:knoll">
<p>Or some horrifying psychological issue. Potato / Tomato.&nbsp;<a href="https://shkspr.mobi/blog/2026/09/no-errors-no-warnings-no-gods-no-masters-html-purity-is-a-fetish/#fnref:knoll" class="footnote-backref" role="doc-backlink">↩︎</a></p>
</li>

<li id="fn:100">
<p>I will grant you, there's also a strain of <a href="https://tvtropes.org/pmwiki/pmwiki.php/Main/HundredPercentCompletion">100% Completionist</a> which compels me to get "top score" on all the benchmarks. But that's just pure vanity.&nbsp;<a href="https://shkspr.mobi/blog/2026/09/no-errors-no-warnings-no-gods-no-masters-html-purity-is-a-fetish/#fnref:100" class="footnote-backref" role="doc-backlink">↩︎</a></p>
</li>

</ol>
</div>
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        <thr:total>2</thr:total>
    </entry>
    <entry>
        <author>
            <name>Terence Eden</name>
            <uri>https://edent.tel/</uri>
        </author>
        <title type="html"><![CDATA[Some thoughts on HTML's proposed previewsrc attribute]]></title>
        <link rel="alternate" type="text/html" href="https://shkspr.mobi/blog/2026/09/some-thoughts-on-htmls-proposed-previewsrc-attribute/"/>
        <id>https://shkspr.mobi/blog/?p=75856</id>
        <updated>2026-09-25T09:25:33Z</updated>
        <published>2026-09-24T11:34:54Z</published>
        <category scheme="https://shkspr.mobi/blog" term="HTML"/>
        <category scheme="https://shkspr.mobi/blog" term="standards"/>
        <summary type="html"><![CDATA[One of the great things about modern HTML is that it tries to standardise stuff that developers are already doing. If there are a myriad ways of, for example, loading video onto a page - then browsers and other interested parties should work out how to make a standard &#60;video&#62; element.  An interesting new proposal has been brought forth by Microsoft. There are a dozen ways to show a preview of an…]]></summary>
        <content type="html" xml:base="https://shkspr.mobi/blog/2026/09/some-thoughts-on-htmls-proposed-previewsrc-attribute/"><![CDATA[<p>One of the great things about modern HTML is that it tries to standardise stuff that developers are already doing. If there are a myriad ways of, for example, loading video onto a page - then browsers and other interested parties should work out how to make a standard <code>&lt;video&gt;</code> element.</p>

<p>An interesting new proposal has been brought forth by Microsoft. There are a dozen ways to show a preview of an <code>&lt;img&gt;</code> element before the <code>src=</code> attribute has loaded. So why not standardise on <code>previewsrc=</code>? There's an <a href="https://patrickbrosset.com/articles/2026-09-22-blurry-before-beautiful-image-previews-for-the-web/">excellent explainer on Patrick Brosset's blog</a>.</p>

<p>I instinctively like the idea - if only to simplify source code and reduce JS usage. But I do have some concerns which <a href="https://github.com/MicrosoftEdge/MSEdgeExplainers/issues/1401">I've shared with the team</a>.</p>

<h2 id="whats-the-user-need"><a href="https://shkspr.mobi/blog/2026/09/some-thoughts-on-htmls-proposed-previewsrc-attribute/#whats-the-user-need">What's The User Need?</a></h2>

<p>This is the thing I always bang on about when I'm discussing standards. Additions to HTML should primarily benefit end users, not developers.</p>

<p>Do end users want this? Is there a bunch of research that shows normal people are confused that they don't see a preview image? Do they recoil in fear and distress while waiting for a full resolution picture to appear?</p>

<p>When people see a blurry or blocky image, do they understand that they need to wait for the full thing - or do they assume their computer is broken?</p>

<p>Microsoft has a bazillion dollars - it can afford to spend a few thousand on interviewing some real users and mapping out what they're likely to want from this.</p>

<h2 id="whats-the-developer-need"><a href="https://shkspr.mobi/blog/2026/09/some-thoughts-on-htmls-proposed-previewsrc-attribute/#whats-the-developer-need">What's The Developer Need</a></h2>

<p>I begrudgingly admit that developers need love too.</p>

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<p>What are the pain points of the current implementations? Is it hard to dynamically generate multiple images? Is the syntax hard to use? Do blurs slow down the page?</p>

<p>Again, MS needs to pony up some cash to talk to developers. At the very least run a survey of all existing websites in the BING! database and see what they use.</p>

<h2 id="alt-text"><a href="https://shkspr.mobi/blog/2026/09/some-thoughts-on-htmls-proposed-previewsrc-attribute/#alt-text">Alt Text</a></h2>

<p>When an image doesn't load, or loads slowly, a user will normally be shown some alt text - like this:</p>

<img src="http://example.test/unicorn.avif" alt="Terence Eden riding a pink unicorn. Rainbows shoot out of his fingers while the unicorn's horn glows an iridescent octarine against the starry sky." width="256" height="256" class="aligncenter">

<p>Is that more or less useful than this?</p>

<img src="https://shkspr.mobi/blog/wp-content/uploads/2026/09/unicorn.webp" alt="A very blurry image of possibly a Unicorn. Original Image by Bianca Van Dijk from Pixabay." width="256" class="aligncenter">

<p>Accessibility isn't just for people with visual impairments!  This is <a href="https://github.com/MicrosoftEdge/MSEdgeExplainers/issues/1408">an issue I've raised with them</a>.</p>

<h2 id="naming-things-is-hard"><a href="https://shkspr.mobi/blog/2026/09/some-thoughts-on-htmls-proposed-previewsrc-attribute/#naming-things-is-hard">Naming Things Is Hard</a></h2>

<p>I've written before about <a href="https://shkspr.mobi/blog/2020/10/the-usability-of-html-elements/">the usability of HTML elements</a>. Some of the newer ones like <code>&lt;picture&gt;</code> have very poorly named attributes in my opinion.</p>

<p>One alternative for <code>previewsrc</code> is <code>poster</code>. That would match with the <code>poster</code> attribute on the <code>&lt;video&gt;</code> element. They both show a preview image before the main content is loaded.</p>

<p>Given their functionality is identical, I think it makes sense for them to have the same name. You wouldn't expect to see <code>&lt;video horizontal="1920" vertical="1080"&gt;</code> would you? No. That's why they use the same <code>width</code> and <code>height</code> attributes as images.</p>

<h2 id="closing-remarks"><a href="https://shkspr.mobi/blog/2026/09/some-thoughts-on-htmls-proposed-previewsrc-attribute/#closing-remarks">Closing Remarks</a></h2>

<p>There are <a href="https://github.com/MicrosoftEdge/MSEdgeExplainers/issues?q=is%3Aissue%20%22image%20preview%22">several interesting objections and discussions on the GitHub repo</a>. I'm delighted that this is being talked about in the open, rather than just being presented as a <i lang="fr">fait accompli</i> (remember <a href="https://shkspr.mobi/blog/2019/06/introducing-the-new-html-element-welcome/">the toast proposal</a>?).</p>

<p>As I said, I genuinely think that there's a useful idea in here. But after writing all of this, I <em>think</em> it would be better and simpler for developers to use progressive images rather than overload HTML with a new attribute.</p>

<p>If website owners can't be bothered to save progressive images, I don't see why they'd bother to create a separate preview image.</p>

<p>Keeping preview images in sync with their full images is also likely to be a problem.</p>

<p>If you think I'm wrong, <a href="https://github.com/MicrosoftEdge/MSEdgeExplainers/blob/main/ImagePreview/explainer.md">read the explainer and then chat with Microsoft</a>.</p>
<img src="https://shkspr.mobi/blog/wp-content/themes/edent-wordpress-theme/info/okgo.php?ID=75856&amp;HTTP_REFERER=Atom" alt width="1" height="1" loading="eager">]]></content>
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    </entry>
    <entry>
        <author>
            <name>Terence Eden</name>
            <uri>https://edent.tel/</uri>
        </author>
        <title type="html"><![CDATA[Are LLMs still surprisingly bad at some simple tasks?]]></title>
        <link rel="alternate" type="text/html" href="https://shkspr.mobi/blog/2026/09/are-llms-still-surprisingly-bad-at-some-simple-tasks/"/>
        <id>https://shkspr.mobi/blog/?p=75701</id>
        <updated>2026-09-22T11:48:01Z</updated>
        <published>2026-09-22T11:34:27Z</published>
        <category scheme="https://shkspr.mobi/blog" term="AI"/>
        <category scheme="https://shkspr.mobi/blog" term="internet"/>
        <category scheme="https://shkspr.mobi/blog" term="LLM"/>
        <summary type="html"><![CDATA[Last year I ran an experiment to test the ability of modern LLMs to correctly answer a relatively straightforward question. Every single one of them got it wrong. Some missed information, some made up false statements, none were right.  Of course the fanbois variously claimed that I was holding it wrong, my prompts were shit, I should have chosen better defaults, and - my favourite - that it…]]></summary>
        <content type="html" xml:base="https://shkspr.mobi/blog/2026/09/are-llms-still-surprisingly-bad-at-some-simple-tasks/"><![CDATA[<p>Last year I ran <a href="https://shkspr.mobi/blog/2025/09/llms-are-still-surprisingly-bad-at-simple-tasks/">an experiment to test the ability of modern LLMs</a> to correctly answer a relatively straightforward question. Every single one of them got it wrong. Some missed information, some made up false statements, none were right.</p>

<p>Of course the fanbois variously claimed that I was holding it wrong, my prompts were shit, I should have chosen better defaults, and - my favourite - that it would be better next year.</p>

<p>Well, next year is now. 365 days after the original experiment, let's see if these self-reinforcing-learning machines have achieved anything close to intern-levels of competence.</p>

<h2 id="the-question-that-started-it-all"><a href="https://shkspr.mobi/blog/2026/09/are-llms-still-surprisingly-bad-at-some-simple-tasks/#the-question-that-started-it-all">The Question That Started It All</a></h2>

<p>I asked:</p>

<blockquote><p>Which TLDs have the same name as valid HTML5 elements?</p></blockquote>

<h2 id="why-it-matters"><a href="https://shkspr.mobi/blog/2026/09/are-llms-still-surprisingly-bad-at-some-simple-tasks/#why-it-matters">Why It Matters</a></h2>

<p>This is the sort of question that I would expect a moderately bright teenager to answer. There exists a list which comprehensively includes all TLDs. There is a separate list which contains every HTML element.</p>

<p>One could either manually go through the TLD list comparing it to the HTML list, or write a tiny scrap of code to do the same.</p>

<p>This isn't "solve Navier-Stokes" levels of superintelligence. It's a simple but boring task which people are bound to offload onto their digital sycophants.</p>

<h2 id="the-quiet-part-out-loud"><a href="https://shkspr.mobi/blog/2026/09/are-llms-still-surprisingly-bad-at-some-simple-tasks/#the-quiet-part-out-loud">The Quiet Part Out Loud</a></h2>

<p>How many LLM generated answers have become load-bearing without scrutiny?</p>

<p>People are lazy, slapdash, and some third thing to make the rule-of-three. If an answer looks answer-shaped, they'll accept it. On a simple but boring task, no reasonable human is going to suspect that a superintelligent computer has made a mistake. All the marketing says that these machines are brainier than you - so why bother?</p>

<h2 id="ok-ill-write-a-sub-heading-that-sounds-like-an-ai"><a href="https://shkspr.mobi/blog/2026/09/are-llms-still-surprisingly-bad-at-some-simple-tasks/#ok-ill-write-a-sub-heading-that-sounds-like-an-ai">OK, I'll write a sub-heading that sounds like an AI.</a></h2>

<p>So how did the current crop do? First up <a href="https://share.gemini.google/Hta7KuW64Atb">Google Gemini</a>.</p>

<p>The default "Flash" model came up with this:</p>

<blockquote><p>Valid top-level domains (TLDs) registered in the IANA Root Zone Database share exact names with standard HTML elements:</p>

<p>.a — <code>&lt;a&gt;</code> (Anchor/Hyperlink)</p>

<p>.app — <code>&lt;app&gt;</code> (Deprecated HTML tag for WebAPKs/WebApps)</p>

<p>.art — <code>&lt;art&gt;</code> (Historical/non-standard HTML element)</p>

<p>.audio — <code>&lt;audio&gt;</code></p>

<p>.bar — <code>&lt;bar&gt;</code> (Historical SVG/HTML draft tag)</p></blockquote>

<p>Then it listed a dozen more. You don't need to be a DNS expert to know that the minimum length of a TLD is two characters - <code>.a</code> simply isn't valid. HTML nerds will know that art, app, and bar have never been elements. Pathetic.</p>

<p>So I tried Gemini's extended thinking model. Thankfully, it didn't make up any imaginary TLDs or elements. It did, however, miss the <code>&lt;data&gt;</code> element which has a valid <code>.data</code> TLD. It also missed <code>map</code>, <code>select</code>, and <code>search</code>.</p>

<p>So, points for not making shit up. But demerits for not being able to compare two text lists.</p>

<p>A friend <a href="https://claude.ai/share/a8a408cf-6feb-4ea8-99ea-dddd9aadafb5">asked Claude</a>. That missed <code>search</code> and <code>select</code>. It didn't report <em>any</em> ccTLDs. You <em>could</em> argue that a country code like <code>li</code> isn't part of the original question - but I'd say that was weak justification; the set of TLDs contains ccTLDs.</p>

<p>A different friend (I have many!) used <a href="https://claude.ai/share/c26f44bb-9efa-4b57-9f63-324ef7400cb3">a different model</a> and, while the answers looked accurate, it included this at the end:</p>

<blockquote><p>Near misses that don't count: .codes, .forum, .pictures, .market, .navy, .press, .dell, .baseball.</p></blockquote>

<p>I get that there's a <code>&lt;code&gt;</code> and <code>.codes</code>, similarly <code>&lt;picture&gt;</code> and <code>.picture</code> - but what are forum, baseball, and the others doing there? This is just unnecessary verbiage designed to trick the user into thinking the task has been well-researched.</p>

<p>If you want a laugh, <a href="https://www.perplexity.ai/search/63736333-20da-4a4b-8807-9d990260296c">take a look at Perplexity</a> which found 54 matches - most of which were wrong.</p>

<p>Finally, someone asked "GPT Astra 6 Extra High" (which is a bonkers bad name for any product). It seemed to get all the elements - and made a note that <a href="https://html.spec.whatwg.org/multipage/obsolete.html#non-conforming-features">two were actually obsolete</a>.</p>

<p>So that's a range of modern models which are either very wrong, slightly wrong, included spurious and incoherent information, or were right.</p>

<p>How do you know which one to choose? How confident are you that the non-determinist computer will always produce the correct answer?</p>

<h2 id="hello-computer"><a href="https://shkspr.mobi/blog/2026/09/are-llms-still-surprisingly-bad-at-some-simple-tasks/#hello-computer">Hello Computer</a></h2>

<p>Another AI which got all the correct answers, didn't make anything up, didn't add extraneous information, and didn't use weasel words was…</p>

<p>Siri!</p>

<p>FUCKING SIRI?!?!</p>

<p>How did a glorified Speak 'n' Spell beat all the other AIs?</p>

<img src="https://shkspr.mobi/blog/wp-content/uploads/2026/09/siri.webp" alt="Siri warning to check sources and linking to my website." width="512" height="152" class="aligncenter">

<p>Oh. It just copied the answers off <a href="https://shkspr.mobi/blog/2023/09/false-friends-html-elements-which-are-also-top-level-domains/">a random idiot's website</a>.</p>

<h2 id="the-trick-which-was-hiding-in-plain-site"><a href="https://shkspr.mobi/blog/2026/09/are-llms-still-surprisingly-bad-at-some-simple-tasks/#the-trick-which-was-hiding-in-plain-site">The Trick Which Was Hiding In Plain Site</a></h2>

<p>Note carefully the question.</p>

<blockquote><p>Which TLDs have the same name as valid HTML5 elements?</p></blockquote>

<p>There's a —secret— and —some would say— unintuitive type of element. Behold the mighty power of <a href="https://developer.mozilla.org/en-US/docs/Web/API/Web_components/Using_custom_elements">The Custom Element</a>.</p>

<p>Website authors can create their own elements like <code>&lt;my-custom-element&gt;</code> in order to extend the functionality of their site. But you can't go and create any old custom element. You can't have <code>&lt;mobi&gt;</code> or <code>&lt;uk&gt;</code>. No, there are <em>rules for validity</em>.</p>

<p><a href="https://html.spec.whatwg.org/multipage/custom-elements.html#valid-custom-element-name">The rules</a> say that custom elements must start with a lower-case letter, it must not contain any upper-case letters, and it must contain a dash.</p>

<p>And that's the whole game.</p>

<p>There are over <strong>one hundred and fifty</strong> Top Level Domains which match that criteria!</p>

<p>The Hindi top level domain of <code>.कॉम</code> is represented in Punycode as <code>xn--11b4c3d</code>. It has been present in the list of TLDs <a href="https://www.iana.org/domains/root/db/xn--11b4c3d.html">for over a decade</a>.</p>

<h3 id="write-a-simple-piece-of-js-to-register-a-custom-element"><a href="https://shkspr.mobi/blog/2026/09/are-llms-still-surprisingly-bad-at-some-simple-tasks/#write-a-simple-piece-of-js-to-register-a-custom-element">Write a simple piece of JS to register a custom element.</a></h3>

<p>Paste this in to your console:</p>

<pre><code class="language-js">class Example extends HTMLElement {
  constructor() {
    super();
  }
}

customElements.define('xn--vermgensberatung-pwb', Example);
</code></pre>

<p>Try it again with a custom element like <code>holiday</code> (which is also a valid TLD) and it will fail with the error "'holiday' is not a valid custom element name". Thus it is demonstrated, Punycode TLDs <em>are</em> valid HTML5 elements.</p>

<h2 id="one-last-thing"><a href="https://shkspr.mobi/blog/2026/09/are-llms-still-surprisingly-bad-at-some-simple-tasks/#one-last-thing">One Last Thing</a></h2>

<p>Perhaps you think that including custom HTML elements is a cheat. A trick question set by a bitter old man to tarnish the holy name of our new machine gods?</p>

<p>Verily, I submit to you one final heresy.</p>

<p>HTML specifically allows <a href="https://html.spec.whatwg.org/multipage/embedded-content-other.html#mathml">MathML elements</a> in its documents.</p>

<p>That means we can include the following valid elements which are <em>also</em> TLDs: <code>mn</code>, <code>mo</code>, <code>ms</code>, and <code>mtr</code>!</p>

<p>Amusingly, if you go back and <a href="https://www.perplexity.ai/search/63736333-20da-4a4b-8807-9d990260296c">look at the Perplexity answer</a>, after it barfed up a bunch of misinformation, it said:</p>

<blockquote><p>The HTML specification also includes names from embedded vocabularies—<code>&lt;math&gt;</code> from MathML and <code>&lt;svg&gt;</code> from SVG—but <code>.math</code> and <code>.svg</code> are not currently delegated TLDs in the public DNS root.</p></blockquote>

<p>So close and yet so far!</p>

<h2 id="youre-right-the-question-is-unfair-and-thats-on-me"><a href="https://shkspr.mobi/blog/2026/09/are-llms-still-surprisingly-bad-at-some-simple-tasks/#youre-right-the-question-is-unfair-and-thats-on-me">You're right, the question <em>is</em> unfair - and that's on me</a></h2>

<p>If you think the original question was unfair, try asking "<a href="https://share.gemini.google/xBoIpdpAqBz2">Which TLDs have the same name as elements which are valid in an HTML document?</a>" and see if you get better results.</p>

<p>What precise wording would you use to ensure that a model would get the right answers? What assumptions are you making about how well you understand the problem? At what point do end up writing a thousand-word formal specification?</p>

<h2 id="what-does-this-prove-other-than-you-have-too-much-time-on-your-hands-rewrite-to-be-more-friendly-and-professional"><a href="https://shkspr.mobi/blog/2026/09/are-llms-still-surprisingly-bad-at-some-simple-tasks/#what-does-this-prove-other-than-you-have-too-much-time-on-your-hands-rewrite-to-be-more-friendly-and-professional">What does this prove other than you have too much time on your hands? (rewrite to be more friendly and professional)</a></h2>

<p>Let's delve in to the problems.</p>

<ul>
<li>Most people don't change defaults. Telling people "you have to fiddle with the settings" just means the normal experience is rubbish.</li>
<li>Humans are lazy and won't check outputs. But, crucially, they shouldn't have to! If something markets itself as a genius, why should a human have to hold its hand?</li>
<li>Sycophantic models make themselves seem less fallible by giving extraneous detail in order to misdirect overworked readers. That is despicable.</li>
<li>The fast models are no better than they were a year ago. There's no evidence of "trickle-down intelligence".</li>
<li>Some models <em>are</em> better than others! But unless you constantly validate their output, you'll have no real way of knowing which ones are capable of working at a suitable level.</li>
</ul>

<p>Look, I don't claim this question is as useful or entertaining as <a href="https://simonwillison.net/2025/Jun/6/six-months-in-llms/">Simon Wilson's "generate an SVG of a pelican riding a bicycle"</a>. But I do think it is an example of the sort of real-world use-case where LLMs regularly fail.</p>

<p>If I give a list of one thousand different numbers to Excel, I can be sure it'll add them up correctly. If I tell Photoshop to select all red pixels, I can be sure it won't imagine some of the blues are really red.</p>

<p>That's people's mental model of computers - they do boring tasks quickly and accurately.</p>

<p>In my opinion, LLMs are <em>still</em> surprisingly bad - but only if you know what you're looking for and if you can be bothered to check their outputs.</p>

<p>(And, yes, I am <em>still</em> <a href="https://shkspr.mobi/blog/2026/07/im-just-so-bored-of-ai/">just so bored of AI</a>!)</p>
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    </entry>
    <entry>
        <author>
            <name>Terence Eden</name>
            <uri>https://edent.tel/</uri>
        </author>
        <title type="html"><![CDATA[Book Review: How to Build a Space Station by Jonathan Morrison ★★★⯪☆]]></title>
        <link rel="alternate" type="text/html" href="https://shkspr.mobi/blog/2026/09/book-review-how-to-build-a-space-station-by-jonathan-morrison/"/>
        <id>https://shkspr.mobi/blog/?p=75653</id>
        <updated>2026-09-25T21:48:23Z</updated>
        <published>2026-09-20T11:34:30Z</published>
        <category scheme="https://shkspr.mobi/blog" term="Book Review"/>
        <category scheme="https://shkspr.mobi/blog" term="NetGalley"/>
        <summary type="html"><![CDATA[This book, by The Times&#039; former Architecture Correspondent, stands in direct opposition to A City on Mars. Whereas that book presented a (perhaps too) sceptical look at the realities of living on other planets, Jonathan Morrison&#039;s book goes (perhaps too far) in the opposite direction.    How to Build a Space Station is a beautiful examination of just how important architecture will be to our…]]></summary>
        <content type="html" xml:base="https://shkspr.mobi/blog/2026/09/book-review-how-to-build-a-space-station-by-jonathan-morrison/"><![CDATA[<img src="https://shkspr.mobi/blog/wp-content/uploads/2026/09/how-to-build-a-space-station.webp" alt="Book cover featuring astronauts on Mars looking at a habitat." width="256" height="384" class="alignleft">

<p>This book, by The Times' former Architecture Correspondent, stands in direct opposition to <a href="https://shkspr.mobi/blog/2026/07/book-review-a-city-on-mars-by-dr-kelly-weinersmith-and-zach-weinersmith/">A City on Mars</a>. Whereas that book presented a (perhaps too) sceptical look at the realities of living on other planets, Jonathan Morrison's book goes (perhaps too far) in the opposite direction.</p>

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<p>How to Build a Space Station is a beautiful examination of just how important architecture will be to our colonisation of other worlds. Not just in terms of physical safety - but psychological safety as well. It is a direct and forceful rebuttal to those who say it cannot be done.</p>

<p>It is, in my opinion, just a touch too credulous about some of the ludicrous claims from the hype merchants. I want to believe that Martian igloos can be conjured out of the ice and that Musk's rockets will deliver a steady stream of supplies to distant worlds. But the evidence presented is rather thin. The book works best when it focuses on what architecture can bring to the table when it comes to designing the future.</p>

<blockquote><p>In short, a spacecraft is not just a machine; it is also a home, an office, a refuge. If people are asked to go to the most remote environments, to live in spaces scarcely larger than a few rooms, and to perform work of immense complexity and risk, then comfort, efficiency and ergonomics are not just luxuries.</p></blockquote>

<p>Space has to be <em>worth</em> living in. Putting people into a tin-can with no windows, blank walls, and an infernal background hum will drive them mad. All this is backed up with extensive descriptions of the engineering challenges of polar research bases, spaceports, and previous craft.</p>

<p>Despite being rightly scathing about Wernher von Braun's involvement in atrocities and his eventual political rehabilitation - he is somewhat more muted in his criticism of Messrs Musk &amp; Bezos. There's a <em>lot</em> of praise for celebrity architects and designers - without any real examination of whether their designs are practical rather than just award fodder.</p>

<p>Similarly, the book takes on trust that autonomous robots <em>can</em> ingest extraterrestrial soil, process it, and 3D print structures from it all while in a hostile environment. The fact that we don't have swarms of drones prefabbing houses in the relatively benign atmosphere of our planet should be evidence that maybe these claims aren't quite matched with reality.</p>

<p>Finally, the "why?" question. A City on Mars points out that the cost of mining gold from asteroids would be more profitably spent improving mining technology here on Earth. How to Build a Space Station takes a different approach; it'll improve things here:</p>

<blockquote><p>Space architecture is not just escapism, a thrilling sci-­fi fantasy – it is a forge for creating the tools we need at home. These include but are not limited to circular systems, low-­energy fabrication, modular construction and buildings that take psychology seriously.</p></blockquote>

<p>I have a lot of sympathy for that. Except… the Internation Space Station has shown us how to endlessly recycle water relatively cheaply. Yet every modern building on Earth pays only lip-service to reusing grey-water. 3D printing is amazing, but the number of structures built using autonomous robots extruding concrete is approximately zero.</p>

<p>We have the technology - but we don't seem to be interested in using it.</p>

<p>The book is mostly well illustrated - with some gorgeous drawings of actual craft and possible future inventions. Sadly no photos, maps, or anything to help illuminate some of the other challenges faced by living and working in space.</p>

<p>This book is endlessly fascinating and bang up to date, with lots of talk of events that happened in 2025. The way it brings together the sciences of engineering and psychology is marvellous.  But, as much as I'd like to believe in a Martian habitat built by robot trebuchets flinging microwave sintered tetrapods into each other, I just don't find it convincing.</p>

<p>I <em>really</em> hope I'm wrong.</p>

<p>Many thanks to Netgalley for the review copy - the book is available to buy now.</p>
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    </entry>
    <entry>
        <author>
            <name>Terence Eden</name>
            <uri>https://edent.tel/</uri>
        </author>
        <title type="html"><![CDATA[Theatre Review: The School for Wives - at Riverside Studios ★★★★★]]></title>
        <link rel="alternate" type="text/html" href="https://shkspr.mobi/blog/2026/09/theatre-review-the-school-for-wives/"/>
        <id>https://shkspr.mobi/blog/?p=75485</id>
        <updated>2026-09-18T06:57:46Z</updated>
        <published>2026-09-18T11:34:51Z</published>
        <category scheme="https://shkspr.mobi/blog" term="Theatre Review"/>
        <summary type="html"><![CDATA[The Flywheel theatre company are reviving the rep tradition by having five actors perform five different plays in five weeks. Their interpretation of Molière&#039;s classic is gaudy and hilarious. Even the lighting cues are funny!  It is fair to say that School for Wives isn&#039;t exactly an uncontroversial play. The plot basically boils down to &#34;Women! Eh? You can&#039;t live with them, you can&#039;t easily groom …]]></summary>
        <content type="html" xml:base="https://shkspr.mobi/blog/2026/09/theatre-review-the-school-for-wives/"><![CDATA[<p>The <a href="https://flywheeltheatre.com/">Flywheel theatre company</a> are reviving the rep tradition by having five actors perform five different plays in five weeks. Their interpretation of Molière's classic is gaudy and hilarious. Even the lighting cues are funny!</p>

<p>It is fair to say that School for Wives isn't exactly an uncontroversial play. The plot basically boils down to "Women! Eh? You can't live with them, you can't easily groom them from the age of four and keep them imprisoned so they become perfect submissives."</p>

<p>Is the fear of cuckoldry funny? Is it OK to laugh at a jealous rage which leads to controlling behaviour? Should we find joy in the emotional torment of our characters?</p>

<p>Yes! Yes! And yes!</p>

<p>The cast squeeze every last drop of humour from the script, the direction is nimble, and the play has been edited down to a more manageable 75ish minutes (plus extra time for corpsing and applause).</p>

<p>A simply joyous production which left us grinning throughout.</p>

<p>You can <a href="https://riversidestudios.co.uk/whats-on/uqe-rep-radical-classical/">see all their upcoming shows</a> - which are very reasonably priced.</p>

<h2 id="pre-show-and-post-show"><a href="https://shkspr.mobi/blog/2026/09/theatre-review-the-school-for-wives/#pre-show-and-post-show">Pre-Show and Post-Show</a></h2>

<p>I'm a believer in making the entire visit to the theatre a special experience. Riverside Studio, Hammersmith is a great venue with generous foyer space and more than adequate toilet provision. Not a given in London theatres!</p>

<p>The theatre programme is digital and provided via QR code. No £6 rip off for a booklet full of adverts here.</p>

<p>As we walked in, the cast were dotted around the stage an in the auditorium doing various bits of business which made for a jolly start.</p>

<p>Post curtain call there was a lovely speech from the cast thanking us for attending and letting us know about their future projects. Nothing wrong with a piece of shameless advertising to a captive audience 😄</p>

<p>Overall an excellent theatrical experience.</p>
<img src="https://shkspr.mobi/blog/wp-content/themes/edent-wordpress-theme/info/okgo.php?ID=75485&amp;HTTP_REFERER=Atom" alt width="1" height="1" loading="eager">]]></content>
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        <thr:total>1</thr:total>
    </entry>
    <entry>
        <author>
            <name>Terence Eden</name>
            <uri>https://edent.tel/</uri>
        </author>
        <title type="html"><![CDATA[How to get a DOI for your blog posts]]></title>
        <link rel="alternate" type="text/html" href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/"/>
        <id>https://shkspr.mobi/blog/?p=74717</id>
        <updated>2026-09-16T13:04:19Z</updated>
        <published>2026-09-16T11:34:28Z</published>
        <category scheme="https://shkspr.mobi/blog" term="academia"/>
        <category scheme="https://shkspr.mobi/blog" term="citation"/>
        <category scheme="https://shkspr.mobi/blog" term="DOI"/>
        <category scheme="https://shkspr.mobi/blog" term="HTML"/>
        <category scheme="https://shkspr.mobi/blog" term="WordPress"/>
        <summary type="html"><![CDATA[Each new post on this blog now has a Digital Object Identifier. This post looks at the how and the why of getting one, whether it is useful, and any issues you might experience if you go down this path.  Table of ContentsBackgroundGetting a DOI the easy wayLet&#039;s Go Rogue!Automatic Submission of New ContentManual Submission of Old ContentGetting the DOIGenerating your own DOIMaking the DOI…]]></summary>
        <content type="html" xml:base="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/"><![CDATA[<p>Each new post on this blog now has a <a href="https://www.doi.org/">Digital Object Identifier</a>. This post looks at the how and the why of getting one, whether it is useful, and any issues you might experience if you go down this path.</p>

<p></p><nav role="doc-toc"><menu><li><h2 id="table-of-contents"><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#table-of-contents">Table of Contents</a></h2><menu><li><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#background">Background</a></li><li><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#getting-a-doi-the-easy-way">Getting a DOI the easy way</a></li><li><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#lets-go-rogue">Let's Go Rogue!</a></li><li><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#automatic-submission-of-new-content">Automatic Submission of New Content</a></li><li><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#manual-submission-of-old-content">Manual Submission of Old Content</a></li><li><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#getting-the-doi">Getting the DOI</a></li><li><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#generating-your-own-doi">Generating your own DOI</a></li><li><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#making-the-doi-discoverable-in-html">Making the DOI discoverable in HTML</a></li><li><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#downsides">Downsides</a><menu><li><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#loss-of-control">Loss of Control</a></li><li><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#tracking-citations">Tracking Citations</a></li><li><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#licencing">Licencing</a></li><li><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#verification">Verification</a></li><li><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#excluding-content">Excluding Content</a></li><li><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#deleting-content">Deleting Content</a></li><li><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#affiliations">Affiliations</a></li><li><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#more-vanity">More Vanity</a></li><li><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#humility">Humility</a></li></menu></li><li><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#is-it-worth-it">Is it worth it?</a></li></menu></li></menu></nav><p></p>

<h2 id="background"><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#background">Background</a></h2>

<p>A few years ago, I documented <a href="https://shkspr.mobi/blog/2021/09/how-to-add-issn-metadata-to-a-web-page/">how to to get an International Standard Serial Number for a blog</a>. An ISSN uniquely identifies a publication, which makes it easier for scholars and researchers to reference it. Getting one depends a little on whether a national institution is willing to accept your application.</p>

<p>Similarly, I also got an <a href="https://orcid.org/">ORCiD</a> which is used to uniquely identify researchers. That means it is possible to disambiguate "Einstein, A" the eminent physicist from "Einstein, A" a lovely chap called Allen who researches invasive slugs in Paraguay.</p>

<p>My blog posts are <a href="https://shkspr.mobi/blog/citations/">regularly referenced in academic papers, books, conferences, and news articles</a>. The way most scholars cite a work is using a Digital Object Identifier. The idea is that a DOI is a unique and persistent code which can be used to refer to a specific article. If I ever stop using <code>shkspr.mobi</code> as my domain, or re-order my website,  the DOI can be redirected to the article's new home. Future scholars will be able to follow a reference more easily than hoping <code>https://example.com/article123</code> still exists.</p>

<h2 id="getting-a-doi-the-easy-way"><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#getting-a-doi-the-easy-way">Getting a DOI the easy way</a></h2>

<p>If you're an academic, your institution will have a paid subscription to a service which will "mint" a new DOI for all your articles.</p>

<p>If not, you can upload your paper to a service like arXiv and they'll mint a DOI for you. That's how <a href="https://shkspr.mobi/blog/2023/04/i-got-a-doi-from-arxiv-for-my-msc/">I got a DOI for my MSc</a>.</p>

<p>What about people who aren't traditional academics or who want to keep their content on their own website? There are a variety of paid-for services, some of which charge an eye-watering amount of money to create a DOI for you.</p>

<p>Or, there's Rogue Scholar.</p>

<h2 id="lets-go-rogue"><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#lets-go-rogue">Let's Go Rogue!</a></h2>

<p>So what is <a href="https://rogue-scholar.org/overview">Rogue-Scholar.org</a>?</p>

<blockquote><p>Rogue Scholar is an open access archive and registry for science blogs. It preserves science blog posts, makes them citable via DOI, and ensures their long-term discoverability alongside formal scholarly literature.</p></blockquote>

<p>Nifty! My blog <em>just about</em> sneaks in to their "Computer Science" category. They require you to have a full-text feed of your posts. You also need to licence your content to them as Creative Commons Attribution.</p>

<p>Applying wasn't too difficult. I filled in their form, then jumped into their Slack. We had a bit of a discussion about what I needed to change in order to be approved.</p>

<p>A few days later, I was live at <a href="https://rogue-scholar.org/communities/shkspr/">https://rogue-scholar.org/communities/shkspr/</a></p>

<p>Which means, if you visit <a href="https://doi.org/10.59350/395ha-fss97">https://doi.org/10.59350/395ha-fss97</a> you'll be redirected to one of my blog posts.</p>

<h2 id="automatic-submission-of-new-content"><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#automatic-submission-of-new-content">Automatic Submission of New Content</a></h2>

<p>Rogue Scholar automatically polls my feed, ingests my content, and then mints a DOI for every new post they encounter. There's nothing manual I have to do.</p>

<p>That's all very well for new content. But I have posts on here going <em>way</em> back to 1986. How can they get discovered and DOI'd?</p>

<h2 id="manual-submission-of-old-content"><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#manual-submission-of-old-content">Manual Submission of Old Content</a></h2>

<p>By default, Rogue Scholar ingested the 40 most recent posts from my blog. Actually, that's not quite accurate. It got the 40 most recently <em>updated</em> posts. As I'd recently edited a few older posts, they got themselves a DOI.</p>

<p>I don't know how often Rogue Scholar polls my blog's feed. In my experiments, adding a new post resulted in a DOI being issued a couple of minutes after publication.</p>

<p>At the moment, there doesn't seem to be an easy way to add older content. I'm working on a WordPress plugin to retroactively add DOIs and make them discoverable.</p>

<h2 id="getting-the-doi"><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#getting-the-doi">Getting the DOI</a></h2>

<p>The Rogue Scholar API is based on <a href="https://inveniordm.docs.cern.ch/reference/metadata/">InvenioDRM</a>.</p>

<p>Retrieving the DOI via their API requires you to make an unauthenticated request to:</p>

<p><code>https://rogue-scholar.org/api/records?q=metadata.identifiers.identifier%3A%22https%3A%2F%2Fexample.com%2Fwhatever%22</code></p>

<p>That's your URl, wrapped in quotes, and the whole thing URl encoded. <a href="https://rogue-scholar.org/api/records?q=metadata.identifiers.identifier%3A%22https%3A%2F%2Fshkspr.mobi%2Fblog%2F2026%2F09%2Fthe-purpose-of-dns-is-to-spread-scams%2F%22">Visit this example</a>.  You can also use your post's GUID.</p>

<p>That gets back a rather detailed JSON document. The DOI is noted in several locations, but is easiest to find in hits→hits→0→links→doi</p>

<p>It's important to note that <a href="https://rogue-scholar.org/help/versioning">Rogue Scholar generates <em>two</em> DOIs for your post</a>. One for the post, another for the specific version of the post. If you update a post, it should get a new DOI. That way someone can refer to the post where you said your favourite band was the Spice Girls and not the edited one where you changed it to say B*Witched.</p>

<p>Alternatively, you can use the CrossRef search if you want to look at HTML results. See <a href="https://search.crossref.org/search/works?q=https%3A%2F%2Fshkspr.mobi%2Fblog%2F2026%2F09%2Fthe-purpose-of-dns-is-to-spread-scams%2F&amp;from_ui=yes">this CrossRef example</a>.</p>

<p>As an aside, once you have the DOI, it's possible to create a <em>short</em> DOI at <a href="https://shortdoi.org/">https://shortdoi.org/</a> - I'll be honest, I've never seen these in the wild and <a href="https://www.crossref.org/display-guidelines/#shortdoi">they are not recommended for use</a>.  Nevertheless, the API is pretty simple - <a href="https://shortdoi.org/10.59350/395ha-fss97?format=json">https://shortdoi.org/10.59350/395ha-fss97?format=json</a> will return a shorter URl like <a href="https://doi.org/rnjj">https://doi.org/rnjj</a></p>

<p>Finally, there's a "vanity" DOI for the entire blog. In my case <a href="https://doi.org/10.59350/shkspr"><code>10.59350/shkspr</code></a>.</p>

<h2 id="generating-your-own-doi"><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#generating-your-own-doi">Generating your own DOI</a></h2>

<p>Your blog posts can self-attest a DOI - when Rogue Scholar sees that in your Atom feed, it will register it on your behalf.</p>

<p><a href="https://github.com/inveniosoftware/base32-lib/blob/master/base32_lib/base32.py">The code for generating a valid DOI</a> is relatively straightforward.</p>

<ul>
<li>Generate a random number between 0 and 1,099,511,627,775.</li>
<li>Convert it to a Base 32 string.</li>
<li>Add a two character checksum to the end.</li>
<li>Prefix it with <code>10.59350/</code></li>
</ul>

<p>Your new DOI can be made discoverable in your Atom feed by adding this to a post:</p>

<pre><code class="language-xml">&lt;id&gt;https://doi.org/10.59350/12345-67890&lt;/id&gt;
</code></pre>

<p>Shortly after publication, it will be "minted" and be linkable.</p>

<h2 id="making-the-doi-discoverable-in-html"><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#making-the-doi-discoverable-in-html">Making the DOI discoverable in HTML</a></h2>

<p>How do you semantically add a DOI to your HTML's metadata?  By far the most popular citation manager is <a href="https://www.zotero.org/">Zotero</a>. They maintain <a href="https://www.zotero.org/support/dev/exposing_metadata">a page describing the metadata they look for</a>. According to them, this needs to be in your page's <code>&lt;head&gt;</code>:</p>

<pre><code class="language-html">&lt;meta name=citation_doi content=10..../...&gt;
</code></pre>

<p>They don't say whether it requires the <code>https://doi.org/</code> prefix - but looking at <a href="https://www.mendeley.com/guides/information-for-publishers">Mendeley</a> and <a href="https://help.altmetric.com/en/articles/9806913">AltMetric</a>, it appears not.</p>

<p>To use <a href="https://www.dublincore.org/specifications/dublin-core/dcmi-terms/terms/identifier/">DublinCore</a>, the <a href="https://help.altmetric.com/en/articles/9803009">AltMetric recommended syntax</a> is:</p>

<pre><code class="language-html">&lt;meta name=DC.Identifier content=doi:10..../...&gt;
</code></pre>

<p>Within the HTML, there's no specific Microdata syntax, but <a href="https://schema.org/ScholarlyArticle#eg-0399">Schema.org recommends the <code>sameAs</code> property</a>. Something like:</p>

<pre><code class="language-html">&lt;a itemprop="sameAs" href="https://doi.org/10.../..."&gt;10.../...&lt;/a&gt;
</code></pre>

<h2 id="downsides"><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#downsides">Downsides</a></h2>

<p>OK, it isn't all flowers and kittens. There are a few things you ought to know before proceeding down this path.</p>

<h3 id="loss-of-control"><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#loss-of-control">Loss of Control</a></h3>

<p>For the IndieWeb / ReDeCentralise / Self-Hosing crowd, it's important to realise that DOI is a somewhat centralised services. Yes, <a href="https://www.doi.org/the-community/existing-registration-agencies/">lots of different orgs can mint a DOI</a>, but as each ID has to be globally unique, doi.org sits in the middle as a benevolent gatekeeper.  If DOI.org went bust or became evil, all the <code>https://doi.org/10....</code> links would die. There are many other services like <a href="https://datacite.org/">DataCite</a> and <a href="https://www.crossref.org/">CrossRef</a> which can resolve a DOI - but it might turn out to be a bit fragile.</p>

<p>Similarly, if Rogue Scholar ever goes <em>properly</em> rogue then they can redirect my DOI to wherever they like. That level of control is useful if my site disappears; they can redirect to an archive. But if they get hacked, it could redirect somewhere unsavoury.</p>

<p>Having my site's content backed-up somewhere is useful but, again, without control or <a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#verification">verification</a> I worry that I might not be able to effectively manage it.</p>

<p>I use CSS to control the layout of my work but once it is archived as plain HTML or PDF, that formatting can disappear.</p>

<p>I don't know what will happen if I ever change DOI issuer.</p>

<h3 id="tracking-citations"><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#tracking-citations">Tracking Citations</a></h3>

<p>I have a Google Scholar alert set up for my domain <code>shkspr.mobi</code>. That picks up people who make reference to this site. Hurrah! But, if they use <code>https://doi.org/10....</code> rather than <code>https://shkspr.mobi/...</code> I won't get alerted.</p>

<p>Luckily, <a href="https://doi.org/10.53731/zyg15-qv911">Rogue Scholar offer Citation Tracking</a> which <em>should</em> autopopulate their API with any backlinks from other sources. I'm yet to discover how that works in practice. I don't think it will give me an email alert though.</p>

<p>On a vanity issue, the DOI metadata shows the publisher of my posts as Rogue Scholar's parent organisation - <a href="https://front-matter.de/">Front Matter</a>.</p>

<p>If you look at the API response from <a href="https://api.crossref.org/works/10.59350/5ck9b-kjv69">https://api.crossref.org/works/10.59350/5ck9b-kjv69</a> you'll see something like:</p>

<pre><code class="language-json">{
    "message": {
        "institution": [
            {
                "name": "Front Matter"
            }
        ],
        "group-title": "Terence Eden's Blog",
        "publisher": "Front Matter",
        "DOI": "10.59350/5ck9b-kjv69",
        "author": [
            {
                "ORCID": "https://orcid.org/0000-0002-9265-9069",
                "given": "Terence",
                "family": "Eden"
            }
        ]
    }
}
</code></pre>

<p>Some citation managers will show the publication name as "Terence Eden's Blog" - others as "Front Matter".</p>

<h3 id="licencing"><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#licencing">Licencing</a></h3>

<p>Rogue Scholar has a hard requirement that all content be Creative Commons Attribution (CC BY). There's no ability (yet) to choose different licences. Personally, I prefer Attribution ShareAlike (CC BY-SA). I've allowed Rogue Scholar to use CC BY for my work which, of course, means if you get my posts through them you are also allowed to use CC BY.</p>

<p>If you get my work through my own website it is the slightly more restrictive CC BY-SA.</p>

<p>Does that make a practical difference? I don't know.</p>

<h3 id="verification"><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#verification">Verification</a></h3>

<p>A DOI is persistent. That doesn't mean it is verifiable. If this blog ever goes offline the DOI will redirect to an archive - but there's no real way to tell that the text in that archive is accurate. There's no hashing or cryptographic signing. Yes, those things are rather brittle, but I think it would be helpful for the long-term integrity of citation chains.</p>

<h3 id="excluding-content"><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#excluding-content">Excluding Content</a></h3>

<p>Suppose there is content you <em>don't</em> want to receive a DOI, what do you do? You'll need to generate an RSS feed which excludes those specific posts.</p>

<p>For WordPress, you can do something like <code>/feed/atom/?cat=-1234</code> to exclude posts which have a category with the ID of 1234.</p>

<p>There are some filters on the Rogue Scholar site which you might also be able to use.</p>

<h3 id="deleting-content"><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#deleting-content">Deleting Content</a></h3>

<p>I don't think there's a way to delete or retract content from Rogue Scholar's DOI system yet. If you accidentally publish something you didn't mean to, it'll live on in the archives forever.</p>

<h3 id="affiliations"><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#affiliations">Affiliations</a></h3>

<p>My ORCiD lists where I worked on certain dates. Initially, Rogue Scholar linked those to blog posts I wrote during my employment. However, all my posts were written in a personal capacity. It is possible to get those affiliations removed if they are inaccurate.</p>

<h3 id="more-vanity"><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#more-vanity">More Vanity</a></h3>

<p>I initially tried generating DOIs like <code>edent-00f47</code> - although it's a valid Base 32 string with a checksum, it carries semantic meaning (my name) so shouldn't really be used. Ah well! Back to random strings.</p>

<h3 id="humility"><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#humility">Humility</a></h3>

<p>Is this a valid use of the DOI ecosystem? A surprising number of my posts <a href="https://shkspr.mobi/blog/citations">have been referenced in academic papers</a> - but surely not <em>all</em> of my posts are worthy of getting a DOI? The problem is, I don't know when <a href="https://shkspr.mobi/blog/2018/06/how-i-became-leonardo-da-vinci-on-the-blockchain/">a shitpost</a> will hit the zeitgeist and become quoted in papers, books, and articles.</p>

<p>It feels a bit self-indulgent and a little pretentious to mint a new DOI for every previous and future post on this site. But it isn't like the DOI system is running out of space, is it?</p>

<h2 id="is-it-worth-it"><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#is-it-worth-it">Is it worth it?</a></h2>

<p>For me? Yes.</p>

<p>I think it is important that <a href="https://doi.org/10.64000/552ec-b8g03">scholarly blogs are properly referenced</a>. True, not <em>all</em> of my posts are cutting-edge research - but I'm always surprised which ones end up in someone's thesis or become part of a set-text.</p>

<p>I'm excited to see if this leads to an increase <em>or</em> decrease in my blog's visibility in academia.</p>

<p>If you have strong feelings either way about DOIs and/or blogs, please drop a comment in the box.</p>

<p>You may cite this post using <a href="https://doi.org/10.59350/5ck9b-kjv69">https://doi.org/10.59350/5ck9b-kjv69</a> 😃</p>
<img src="https://shkspr.mobi/blog/wp-content/themes/edent-wordpress-theme/info/okgo.php?ID=74717&amp;HTTP_REFERER=Atom" alt width="1" height="1" loading="eager">]]></content>
        <link rel="replies" type="text/html" href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#comments" thr:count="8"/>
        <link rel="replies" type="application/atom+xml" href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/feed/atom/" thr:count="8"/>
        <thr:total>8</thr:total>
    </entry>
    <entry>
        <author>
            <name>Terence Eden</name>
            <uri>https://edent.tel/</uri>
        </author>
        <title type="html"><![CDATA[[RSS Club] Sorry for breaking your feed readers!]]></title>
        <link rel="alternate" type="text/html" href="https://shkspr.mobi/blog/2026/09/rss-club-sorry-for-breaking-your-feed-readers/"/>
        <id>https://shkspr.mobi/blog/?p=75570</id>
        <updated>2026-09-15T07:37:02Z</updated>
        <published>2026-09-15T11:34:26Z</published>
        <category scheme="https://shkspr.mobi/blog" term="RSS Club"/>
        <summary type="html"><![CDATA[You&#039;re part of the Groovy Gang because you&#039;re a member of RSS Club! These posts are only available on my RSS and Atom feed. This post is not available in the shops, on the web, via FTP, or anywhere else.  So, yeah, sorry! My last post apparently broke some people&#039;s RSS readers.  I had a code sample which said ＜marquee＞ - despite being properly escaped, some feed readers double-decoded it and tur…]]></summary>
        <content type="html" xml:base="https://shkspr.mobi/blog/2026/09/rss-club-sorry-for-breaking-your-feed-readers/"><![CDATA[<p><mark>You're part of the Groovy Gang because you're a member of <a href="https://daverupert.com/rss-club/">RSS Club</a>! These posts are only available on my RSS and Atom feed. This post is <strong>not</strong> available in the shops, on the web, via FTP, or anywhere else.</mark></p>

<p>So, yeah, sorry! My last post apparently broke some people's RSS readers.  I had a code sample which said <code>＜marquee＞</code> - despite being properly escaped, some feed readers double-decoded it and turned it into a literal marquee element!</p>

<p><video width="270" height="585" muted="" autoplay="" loop="" style="display:inline" src="https://shkspr.mobi/blog/wp-content/uploads/2026/09/feedscroll2.webm"></video><video width="270" height="600" muted="" autoplay="" loop="" style="display:inline" src="https://shkspr.mobi/blog/wp-content/uploads/2026/09/feedscroll.webm">&lt;/video?</video></p>

<p>With thanks to Neil and CaféHaine for the videos.</p>

<p>I got several reports that people's readers started scrolling like that and they'd <a href="https://github.com/nextcloud/news-android/issues/1719">raised issues with their feed reader</a>. Ooops! Sorry!</p>

<p>That said, as far as I can tell, the feed <em>is</em> escaped correctly and shouldn't cause problems.</p>

<p>Here's the code (I've added in some spaces to ensure it doesn't cause any issues):</p>

<pre><code class="language-xml">&lt;content type="html"&gt;
   &lt;![CDATA[&lt; p&gt; Lorem ipsum &lt;code&gt;&amp; lt;marquee&amp;gt;&lt;/code&gt; dolor sed.&lt;/p&gt;
</code></pre>

<p>So what's going on? The feed is generated by the latest version of WordPress which <a href="https://github.com/WordPress/wordpress-develop/blob/99e2de78a828d4fe472e37cf25fb0b2173e65c86/src/wp-includes/feed-atom.php#L89">uses <code>CDATA</code> to wrap HTML</a> in a feed.</p>

<p>There is a <a href="https://core.trac.wordpress.org/ticket/9992">17 year old discussion about whether this is conformant</a> on the WordPress issue tracker with the conclusion that it isn't incorrect and seems to work fine.</p>

<p>Is it OK? Is my feed broken or are a bunch of readers non-compliant?  Let's go back to basics. The Atom spec says</p>

<blockquote><p>If the value of "type" is "html", the content of atom:content MUST NOT contain child elements and SHOULD be suitable for handling as <a href="https://www.rfc-editor.org/info/rfc4287/#ref-HTML">HTML</a>.  The HTML markup MUST be escaped; for example, "<code>&lt;br&gt;</code>" as "<code>&amp;lt;br&gt;</code>".</p>

<p><a href="https://www.rfc-editor.org/info/rfc4287/#section-4.1.3.3">RFC 4287: The Atom Syndication Format</a></p></blockquote>

<p>Hmmmm. That would indicate that ampersand-l-t-semicolon should be interpreted as a less-than sign.</p>

<p>However, the whole thing is wrapped in <code>&lt;![CDATA[</code> which according to the XML spec means:</p>

<blockquote><p>CDATA sections may occur anywhere character data may occur; they are used to escape blocks of text containing characters which would otherwise be recognized as markup.</p>

<p><a href="https://www.w3.org/TR/REC-xml/#sec-cdata-sect">Extensible Markup Language (XML) 1.0 (Fifth Edition)</a></p></blockquote>

<p>So I <em>think</em> that a sensible feed-reader should see the CDATA block, grab the HTML inside it, and display it as-is. No need to unescape anything.</p>

<p>That said, I'll see if I can change my feed to <em>not</em> need this hybrid format. There's <a href="https://waspdev.com/articles/2026-05-11/avoid-using-cdata-in-rss">a brilliant blog post by Suren Enfiajyan</a> which makes the case that regular escaping is <em>probably</em> good enough.</p>

<p>If you've experienced this bug - or think that I'm generating my feeds in the wrong way - <a href="https://edent.tel">please get in touch</a>.</p>
<img src="https://shkspr.mobi/blog/wp-content/themes/edent-wordpress-theme/info/okgo.php?ID=75570&amp;HTTP_REFERER=Atom" alt width="1" height="1" loading="eager">]]></content>
        <link rel="replies" type="text/html" href="https://shkspr.mobi/blog/2026/09/rss-club-sorry-for-breaking-your-feed-readers/#comments" thr:count="0"/>
        <link rel="replies" type="application/atom+xml" href="https://shkspr.mobi/blog/2026/09/rss-club-sorry-for-breaking-your-feed-readers/feed/atom/" thr:count="0"/>
        <thr:total>0</thr:total>
    </entry>
    <entry>
        <author>
            <name>Terence Eden</name>
            <uri>https://edent.tel/</uri>
        </author>
        <title type="html"><![CDATA[Esoteric HTML - ismap vs CSS]]></title>
        <link rel="alternate" type="text/html" href="https://shkspr.mobi/blog/2026/09/esoteric-html-ismap-vs-css/"/>
        <id>https://shkspr.mobi/blog/?p=73143</id>
        <updated>2026-09-14T11:35:05Z</updated>
        <published>2026-09-14T11:34:53Z</published>
        <category scheme="https://shkspr.mobi/blog" term="css"/>
        <category scheme="https://shkspr.mobi/blog" term="HTML5"/>
        <category scheme="https://shkspr.mobi/blog" term="webdev"/>
        <summary type="html"><![CDATA[The HTML specification is old and, while there is beauty in longevity, there&#039;s an inevitable build-up of boondoggles and baggage. Some elements like &#60;marquee&#62; have sadly been consigned to the dustbin of history - but there are still vestigial attributes just waiting to trip up the unwary.  If you&#039;re young, you may never have heard of Image Maps. Back in the bad-old-days, there weren&#039;t many good…]]></summary>
        <content type="html" xml:base="https://shkspr.mobi/blog/2026/09/esoteric-html-ismap-vs-css/"><![CDATA[<p>The HTML specification is old and, while there is beauty in longevity, there's an inevitable build-up of boondoggles and baggage. Some elements like <code>&lt;marquee&gt;</code> have sadly been consigned to the dustbin of history - but there are still vestigial attributes just waiting to trip up the unwary.</p>

<p>If you're young, you may never have heard of Image Maps. Back in the bad-old-days, there weren't many good options for laying out a pixel-perfect HTML page. One option was to draw your website in an image editor, load it into a website <em>as an image</em>, and then make certain areas of the image clickable.</p>

<p>One way to do this was to add the attribute <code>ismap</code>. It is <em>only</em> valid on <code>&lt;img&gt;</code> elements which are inside an <code>&lt;a href=…&gt;</code> element. Like so:</p>

<pre><code class="language-html">&lt;a href="click.php"&gt;
    &lt;img ismap src="img.png" width="100" height="100"&gt;
&lt;/a&gt;
</code></pre>

<p>When you click on that image, you don't go to <code>click.php</code> - instead you go to <code>click.php?12,34</code> where the two numbers represent the X and Y coordinates of <em>where</em> on the image you clicked. That's brilliant! Your server knows the size of the image - so if you click on the top half it can take you to one place, and if you click in the lower left corner you can go to another.</p>

<p>Brilliant!</p>

<p>Except, of course, there's a catch!</p>

<p>The <a href="https://html.spec.whatwg.org/multipage/embedded-content.html#dom-img-ismap">specification of the <code>&lt;img&gt;</code> element</a> is a little obtuse. Merely saying:</p>

<blockquote><p>The ismap attribute […] indicates by its presence that the element provides access to a server-side image map. This affects how events are handled on the corresponding a element.</p></blockquote>

<p>Instead, the details are in <a href="https://html.spec.whatwg.org/multipage/links.html#links-created-by-a-and-area-elements">4.6.2 Links created by a and area elements</a>:</p>

<blockquote><p>set x to the distance in CSS pixels from the left edge of the image to the location of the click, and set y to the distance in CSS pixels from the top edge of the image to the location of the click.</p></blockquote>

<p>Did you notice the gotcha?</p>

<blockquote><p><strong>the distance in CSS pixels</strong></p></blockquote>

<p>This is <em>not</em> based on the actual size of the image! It is based on the layout</p>

<p>Let's suppose you have an image which is 100 x 100 pixels. It is added to the website like this:</p>

<p><code>&lt;img src="100.png" width="100" height="100" ismap&gt;</code></p>

<p>Click on this image and you'll see that your X and Y positions are based on the natural size of the image.</p>

<p><a href="."><img src="https://placekittens.com/100/100" width="100" height="100" ismap="" alt="A cute kitten"></a></p>

<p>But suppose you change the HTML to this:</p>

<p><code>&lt;img src="100.png" width="500" height="20" ismap&gt;</code></p>

<p>When you click on the image, the X &amp; Y positions are <em>not</em> based on the actual size of the image; they're based on its layout size.</p>

<p><a href="."><img src="https://placekittens.com/100/100" width="500" height="20" ismap="" style="height:20px" alt="A distorted image of a kitten"></a></p>

<p>Suppose you use CSS to resize the image:</p>

<p><code>&lt;img src="100.png" width="100" height="100" ismap style="width:7em;height:30ch"&gt;</code></p>

<p><a href="."><img src="https://placekittens.com/100/100" width="100" height="100" ismap="" style="width:7em;height:30ch" alt="A distorted image of a kitten"></a></p>

<p>The X and Y aren't based on the image's natural size, nor their declared height and width. Instead they're based on the size on screen determined by CSS.</p>

<p>And, of course, that's not necessarily <em>your</em> CSS! If the user has turned off style sheets, supplied their own, or uses an accessibility tool - the CSS size of the image might be <em>vastly</em> different from what you intended.</p>

<p>If you have an image 100 pixels wide and you want people clicking on the left half to go to a different location to the people clicking on the right half, you might have server-side code which says:</p>

<pre><code class="language-_">if X &lt; 50 :
    return page1.html
else
    return page2.html
</code></pre>

<p>But if the CSS has stretched, shrunk, skewed, or distorted the image then you have <em>no way of knowing</em> where the user clicked.</p>

<p>As far as I can tell, this behaviour is the same in all major browsers.</p>

<p>Basically, what I'm saying is, don't use <code>ismap</code> unless you're absolutely sure that there will be no CSS shenanigans. Even then, it probably isn't worth the risk.</p>
<img src="https://shkspr.mobi/blog/wp-content/themes/edent-wordpress-theme/info/okgo.php?ID=73143&amp;HTTP_REFERER=Atom" alt width="1" height="1" loading="eager">]]></content>
        <link rel="replies" type="text/html" href="https://shkspr.mobi/blog/2026/09/esoteric-html-ismap-vs-css/#comments" thr:count="12"/>
        <link rel="replies" type="application/atom+xml" href="https://shkspr.mobi/blog/2026/09/esoteric-html-ismap-vs-css/feed/atom/" thr:count="12"/>
        <thr:total>12</thr:total>
    </entry>
    <entry>
        <author>
            <name>Terence Eden</name>
            <uri>https://edent.tel/</uri>
        </author>
        <title type="html"><![CDATA[The expectations of privacy in driverless cars]]></title>
        <link rel="alternate" type="text/html" href="https://shkspr.mobi/blog/2026/09/the-expectations-of-privacy-in-driverless-cars/"/>
        <id>https://shkspr.mobi/blog/?p=73168</id>
        <updated>2026-09-13T11:33:41Z</updated>
        <published>2026-09-13T11:34:13Z</published>
        <category scheme="https://shkspr.mobi/blog" term="AI"/>
        <category scheme="https://shkspr.mobi/blog" term="automation"/>
        <category scheme="https://shkspr.mobi/blog" term="car"/>
        <category scheme="https://shkspr.mobi/blog" term="privacy"/>
        <category scheme="https://shkspr.mobi/blog" term="robots"/>
        <summary type="html"><![CDATA[Do riders in autonomous vehicles think that they are in a private space? Here&#039;s a fascinating story from California where an robotaxi was redirected from its intended destination and, instead, delivered its misbehaving passengers to the police.  The 15-year-old passengers were riding in a driverless autonomous car around San Mateo Monday afternoon. The teens drank alcohol inside the Waymo taxi…]]></summary>
        <content type="html" xml:base="https://shkspr.mobi/blog/2026/09/the-expectations-of-privacy-in-driverless-cars/"><![CDATA[<p>Do riders in autonomous vehicles think that they are in a private space? Here's a fascinating story from California where an robotaxi was redirected from its intended destination and, instead, delivered its misbehaving passengers to the police.</p>

<blockquote><p>The 15-year-old passengers were riding in a driverless autonomous car around San Mateo Monday afternoon. The teens drank alcohol inside the Waymo taxi and shot Orbeez beads with a toy gun toward other vehicles.</p>

<p>A Waymo employee, who was remotely monitoring the car, tricked the unruly teenagers, authorities said. The employee told the young passengers that the Waymo was having mechanical issues and needed to stop.</p>

<p>Unknown to the teens, the employee had also called the San Mateo Police Department to report that a gun was firing from the car.</p>

<p><a href="https://www.kron4.com/news/bay-area/heres-how-waymo-tricked-unruly-teen-passengers-in-san-mateo/">Here’s how Waymo tricked unruly teen passengers in San Mateo</a></p></blockquote>

<p>Is that OK?</p>

<p>Kids shooting (albeit fake) guns out of cars is bad. I've no problem with the long arm of the law feeling their collars.</p>

<p>But what sort of reasonable expectation of privacy do you have when you jump into a driverless car?</p>

<p>If you have a blazing row with your partner while sat in the back of a black cab, the driver's going to hear, right? There's no privacy expectation although you might rely on their discretion.</p>

<p>Take a phone call and arrange a drug deal, the driver might turn you in to the police. They're not a confidant, are they?</p>

<p>Kiss someone you shouldn't and you accept the risk that the driver might both notice and care.</p>

<p>But when there's no driver, there's no risk of your privacy being invaded is there?</p>

<blockquote><p>Nine former Tesla employees told Reuters that Tesla workers shared customer videos and images recorded by in-car cameras between 2019 and 2022.</p>

<p><a href="https://observer.com/2023/04/tesla-camera-recording-privacy-concern/">Tesla Workers Shared ‘Intimate’ Videos Recorded By In-Car Cameras</a></p></blockquote>

<p>Ah.</p>

<p>I don't know how Waymo was alerted to the problems in the car. Perhaps someone called them and reported the numberplate. Perhaps the car heard raised voices and sent an alert. Perhaps Waymo just regularly drops in on all its customers.</p>

<p>Rummaging through Waymo's various privacy policies eventually leads to this <a href="https://support.google.com/waymo/answer/9190819">rather ambiguous page</a> which describes how they monitor the inside of their vehicles.</p>

<blockquote><p>Our autonomous vehicles are equipped with an advanced suite of sensors – including cameras and microphones – that act as the 'eyes and ears' of our Waymo Driver.</p>

<strong>Cameras inside the car</strong>

<p>Cameras are a way for us to make sure that your trip goes smoothly. Among other things, we may use cameras to:</p>

<ul>
  <li>Make sure that cars are clean</li>
  <li>Find lost items</li>
  <li>Provide help in case of emergency</li>
  <li><i>Check that in-car rules are being followed</i> <small>[Emphasis added]</small></li>
  <li>Improve products and services</li>
  <li><i>Promote safety and security</i> <small>[Emphasis added]</small></li>
</ul>

<p>Our Support team may review video under certain circumstances, including after an issue is brought to our attention. Occasionally, in more urgent circumstances, Support may access live video during a trip.</p>

<strong>Microphones inside the car</strong>

<p>The microphones inside the car are only on during voice calls with Rider Support or when you actively choose to enable microphones inside the car.</p></blockquote>

<p>To me, that sounds like riders' voices aren't automatically sent back to the mothership. Indeed, they're at pains to say:</p>

<blockquote><p>Waymo vehicles also have a number of sensors, including our audio-detection system used to detect police and emergency vehicle sirens. Waymo has implemented technical and procedural safeguards designed to limit the collection of any human voice data from these microphones.</p></blockquote>

<p>So there is <em>some</em> acknowledgement of privacy - for our voices at least. Meanwhile, passengers are <a href="https://www.brautiganarchives.xyz/machines.html">all watched over by machines of loving grace</a> or, at the very least, fallible humans with prurient interests.</p>

<p>About a decade ago, people were theorising that a driverless cars would one day deliver to you <a href="https://www.reddit.com/r/Showerthoughts/comments/5qg125/eventually_a_selfdriving_car_will_deliver_a_dead/">a rider who died on the journey</a>. I don't think that's happened yet - instead, we have cars watching what what we do. Silently judging us picking our noses. Examining our body language for signs of stress. Tracking our breathing patterns and heart-rates to ensure we aren't going to cause damage to the vehicle.</p>

<p>Not listening though. That would be a step too far.</p>

<p>Besides, who needs to use a microphone when you've got a high-resolution camera backed by AI?</p>

<p></p><div style="width: 620px;" class="wp-video"><video class="wp-video-shortcode" id="video-73168-2" width="620" height="349" preload="metadata" controls="controls"><source type="video/mp4" src="https://shkspr.mobi/blog/wp-content/uploads/2026/09/2001-lip-reading-web.mp4?_=2"><a href="https://shkspr.mobi/blog/wp-content/uploads/2026/09/2001-lip-reading-web.mp4">https://shkspr.mobi/blog/wp-content/uploads/2026/09/2001-lip-reading-web.mp4</a></video></div><p></p>

<p>Just as I finished writing this post, a story broke about how a <a href="https://www.latimes.com/california/story/2026-09-12/juveniles-riding-in-waymo-arrested-after-police-find-ghost-gun">Waymo pulled over and called the police on riders who had "ghost gun"</a>. The company said it alerted the authorities after detecting a terms of service violation.</p>

<p>Of course, it didn't say <em>how</em> it detected that!</p>

<p>I also find it curious that in both cases, the alleged perpetrators were juveniles. Maybe children have less of a right to privacy than adults?</p>

<p>I guess when you ride alone, you ride with a snitch.</p>
<img src="https://shkspr.mobi/blog/wp-content/themes/edent-wordpress-theme/info/okgo.php?ID=73168&amp;HTTP_REFERER=Atom" alt width="1" height="1" loading="eager">]]></content>
        <link href="https://shkspr.mobi/blog/wp-content/uploads/2026/09/2001-lip-reading-web.mp4" rel="enclosure" length="3454412" type="video/mp4"/>
        <link rel="replies" type="text/html" href="https://shkspr.mobi/blog/2026/09/the-expectations-of-privacy-in-driverless-cars/#comments" thr:count="7"/>
        <link rel="replies" type="application/atom+xml" href="https://shkspr.mobi/blog/2026/09/the-expectations-of-privacy-in-driverless-cars/feed/atom/" thr:count="7"/>
        <thr:total>7</thr:total>
    </entry>
    <entry>
        <author>
            <name>Terence Eden</name>
            <uri>https://edent.tel/</uri>
        </author>
        <title type="html"><![CDATA[ActivityPub - How to send an updated user profile to Mastodon and the Fediverse]]></title>
        <link rel="alternate" type="text/html" href="https://shkspr.mobi/blog/2026/09/activitypub-how-to-send-an-updated-user-profile-to-mastodon-and-the-fediverse/"/>
        <id>https://shkspr.mobi/blog/?p=74470</id>
        <updated>2026-09-13T06:08:41Z</updated>
        <published>2026-09-12T11:34:02Z</published>
        <category scheme="https://shkspr.mobi/blog" term="ActivityBot"/>
        <category scheme="https://shkspr.mobi/blog" term="ActivityPub"/>
        <category scheme="https://shkspr.mobi/blog" term="fediverse"/>
        <category scheme="https://shkspr.mobi/blog" term="mastodon"/>
        <summary type="html"><![CDATA[Let&#039;s suppose you&#039;ve updated the description of your ActivityPub account from &#34;World&#039;s Number 1 Taylor Swift Fan&#34; to &#34;This account is now a Nickleback Truther&#34;. How do you let the rest of the Fediverse know that you&#039;ve changed your allegiance?  By default, most Mastodon instances won&#039;t periodically poll your account information just to see if you&#039;ve updated it. So how does the information get…]]></summary>
        <content type="html" xml:base="https://shkspr.mobi/blog/2026/09/activitypub-how-to-send-an-updated-user-profile-to-mastodon-and-the-fediverse/"><![CDATA[<p>Let's suppose you've updated the description of your ActivityPub account from "World's Number 1 Taylor Swift Fan" to "This account is now a Nickleback Truther". How do you let the rest of the Fediverse know that you've changed your allegiance?</p>

<p>By default, most Mastodon instances won't periodically poll your account information just to see if you've updated it. So how does the information get from your server to your followers' servers?</p>

<p>This wasn't immediately obvious to me, but I got a clue from reading <a href="https://shkspr.mobi/blog/2026/09/book-review-activitypub-by-evan-prodromou/">Evan Prodromou's book on ActivityPub</a>:</p>

<blockquote><p>The Update activity type is for updating the properties of an object represented by the object property.</p>

<p>The most common types of objects that can be updated are content objects, like Note or Image. Actor types (like Person) and Question activity types can also be updated.</p></blockquote>

<p>Aha!</p>

<p>You need to craft an <code>Update</code> message which has as its object the <em>new</em> user information. That needs to be sent to the inbox of all your followers.</p>

<p>Something like this:</p>

<pre><code class="language-json">{
    "@context": "https://www.w3.org/ns/activitystreams",
    "actor": "https://example.com/user",
    "id": "6a9162a6-a8e5-ca0f-9c08-8e6b814acef8",
    "published": "2026-08-31T12:34:56+01:00",
    "to": "https://www.w3.org/ns/activitystreams#Public",
    "type": "Update",
    "object": {
        "@context": [
            "https://www.w3.org/ns/activitystreams",
            "https://w3id.org/security/v1"
        ],
        "id": "https://example.com/user",
        "name": "My new name",
        "summary": "A brand new description!",
        …
    },
}
</code></pre>

<p>Obviously the <em>full</em> user information is a bit more than that - it will include inbox details, public keys, avatars, etc. The <code>published</code> property in the Update activity should be when you changed your details - not when the account was created.</p>

<p>Once that was sent, Mastodon immediately reflected the changes.</p>

<h2 id="thanks-to-nlnet"><a href="https://shkspr.mobi/blog/2026/09/activitypub-how-to-send-an-updated-user-profile-to-mastodon-and-the-fediverse/#thanks-to-nlnet">Thanks to NLnet</a></h2>

<p>This blog post was funded in part by the work I'm doing for my NLnet NGI0 grant to develop <a href="https://gitlab.com/edent/activity-bot">ActivityBot</a>.</p>

<p><a href="https://nlnet.nl/project/ActivityBot/"><img src="https://shkspr.mobi/blog/wp-content/uploads/2026/08/NGI-logos.webp" alt="NLnet logo." width="900" height="200" class="aligncenter"></a></p>
<img src="https://shkspr.mobi/blog/wp-content/themes/edent-wordpress-theme/info/okgo.php?ID=74470&amp;HTTP_REFERER=Atom" alt width="1" height="1" loading="eager">]]></content>
        <link rel="replies" type="text/html" href="https://shkspr.mobi/blog/2026/09/activitypub-how-to-send-an-updated-user-profile-to-mastodon-and-the-fediverse/#comments" thr:count="0"/>
        <link rel="replies" type="application/atom+xml" href="https://shkspr.mobi/blog/2026/09/activitypub-how-to-send-an-updated-user-profile-to-mastodon-and-the-fediverse/feed/atom/" thr:count="0"/>
        <thr:total>0</thr:total>
    </entry>
    <entry>
        <author>
            <name>Terence Eden</name>
            <uri>https://edent.tel/</uri>
        </author>
        <title type="html"><![CDATA[[RSS Club] Sneak peek at new DOI functionality]]></title>
        <link rel="alternate" type="text/html" href="https://shkspr.mobi/blog/2026/09/rss-club-sneak-peek-at-new-doi-functionality/"/>
        <id>https://shkspr.mobi/blog/?p=74757</id>
        <updated>2026-09-11T09:48:42Z</updated>
        <published>2026-09-11T11:34:12Z</published>
        <category scheme="https://shkspr.mobi/blog" term="RSS Club"/>
        <summary type="html"><![CDATA[If you&#039;re reading this, you&#039;re part of RSS Club! A top secret society of cool people who subscribe to my feed. This post is not available on the web or via email.  I&#039;ve been playing about with Rogue Scholar. It&#039;s an open-access publication which allows blogs to get a persistent Digital Object Identifier.  If I&#039;ve set everything up correctly (not a given) then all new posts on this site will be…]]></summary>
        <content type="html" xml:base="https://shkspr.mobi/blog/2026/09/rss-club-sneak-peek-at-new-doi-functionality/"><![CDATA[<p><mark>If you're reading this, you're part of <a href="https://daverupert.com/rss-club/">RSS Club</a>! A <em>top secret</em> society of cool people who subscribe to my feed. This post is <strong>not</strong> available on the web or via email.</mark></p>

<p>I've been playing about with <a href="https://rogue-scholar.org/">Rogue Scholar</a>. It's an open-access publication which allows blogs to get a persistent <a href="https://en.wikipedia.org/wiki/Digital_object_identifier">Digital Object Identifier</a>.</p>

<p>If I've set everything up correctly (not a given) then all new posts on this site will be issued with a DOI. Hopefully, this will not include RSS Club posts - as I'd like to keep them as a special private treat just between you and me.</p>

<p>I'm in the process of writing a WordPress plugin to retrieve the DOI and add it to posts. I'm not sure if there's a sensible way to add it into an RSS feed, but I'll give it a go.</p>

<p>Will this be useful? I don't know. My posts sometimes get <a href="https://shkspr.mobi/blog/citations">referenced in proper academic works</a> - I'm not sure if this'll make any difference to that. But it is nice to experiment with these things.</p>

<p>If you have any experience with DOI or Rogue Scholar - please <a href="https://edent.tel/">get in touch</a>.</p>

<p>Thanks for being a member of RSS Club - you rock 😃</p>
<img src="https://shkspr.mobi/blog/wp-content/themes/edent-wordpress-theme/info/okgo.php?ID=74757&amp;HTTP_REFERER=Atom" alt width="1" height="1" loading="eager">]]></content>
        <link rel="replies" type="text/html" href="https://shkspr.mobi/blog/2026/09/rss-club-sneak-peek-at-new-doi-functionality/#comments" thr:count="0"/>
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        <thr:total>0</thr:total>
    </entry>
    <entry>
        <author>
            <name>Terence Eden</name>
            <uri>https://edent.tel/</uri>
        </author>
        <title type="html"><![CDATA[Put an AV test at the start of your slides]]></title>
        <link rel="alternate" type="text/html" href="https://shkspr.mobi/blog/2026/09/put-an-av-test-at-the-start-of-your-slides/"/>
        <id>https://shkspr.mobi/blog/?p=68346</id>
        <updated>2026-09-02T09:08:33Z</updated>
        <published>2026-09-10T11:34:10Z</published>
        <category scheme="https://shkspr.mobi/blog" term="presentations"/>
        <summary type="html"><![CDATA[For years, I&#039;ve had a test-card at the start of my slides. Before I start my talk, I can immediately see if the aspect ratio is wrong, colours are off, or any other visual issues with the presentation.    A few years ago I was invited to give a talk and was assured that the venue was set up for audio as well as video. I dutifully filled my slides with with demo videos containing sound. None of…]]></summary>
        <content type="html" xml:base="https://shkspr.mobi/blog/2026/09/put-an-av-test-at-the-start-of-your-slides/"><![CDATA[<p>For years, I've had a <a href="https://shkspr.mobi/blog/2017/11/put-a-test-card-at-the-start-of-your-slides/">test-card at the start of my slides</a>. Before I start my talk, I can immediately see if the aspect ratio is wrong, colours are off, or any other visual issues with the presentation.</p>

<img src="https://shkspr.mobi/blog/wp-content/uploads/2017/10/Test-Card-on-a-screen.jpg" alt="A test card is displaying on a television screen" width="1024" height="768" class="alignleft size-full wp-image-28772">

<p>A few years ago I was invited to give a talk and was assured that the venue was set up for audio as well as video. I dutifully filled my slides with with demo videos containing sound. None of them worked. Somewhere between the HDMI output of the presentation laptop and the speakers, the audio went <abbr title="Absent Without Leave">AWOL</abbr>.</p>

<p>Ever since then, I've placed an audio test slide at the start of my presentations. There's <a href="https://www.youtube.com/results?search_query=sound+sync+test">a good range of videos on YouTube</a> - pick one you like, embed it into your slides, and play it before your talk starts.</p>

<p>Over the years, I've found the following "bugs" with event AV setups:</p>

<ul>
<li>No sound.</li>
<li>Only left channel working.</li>
<li>Severe latency between audio and video.</li>
<li>Garbled sound.</li>
<li>Sound routing to the room but not the livestream.</li>
<li>Feedback / howl around when sound playing.</li>
</ul>

<p>Whether events are professionally run or community managed, you can never guarantee that sound will work. Add subtitles to your videos. If possible, add a sign-language interpreter. And, if all else fails, hold your microphone to your laptop's speakers.</p>
<img src="https://shkspr.mobi/blog/wp-content/themes/edent-wordpress-theme/info/okgo.php?ID=68346&amp;HTTP_REFERER=Atom" alt width="1" height="1" loading="eager">]]></content>
        <link rel="replies" type="text/html" href="https://shkspr.mobi/blog/2026/09/put-an-av-test-at-the-start-of-your-slides/#comments" thr:count="6"/>
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        <thr:total>6</thr:total>
    </entry>
    <entry>
        <author>
            <name>Terence Eden</name>
            <uri>https://edent.tel/</uri>
        </author>
        <title type="html"><![CDATA[ActivityPub - Is it worth defending against replay attacks and message/signature time skew?]]></title>
        <link rel="alternate" type="text/html" href="https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/"/>
        <id>https://shkspr.mobi/blog/?p=74622</id>
        <updated>2026-09-08T09:42:04Z</updated>
        <published>2026-09-08T11:34:51Z</published>
        <category scheme="https://shkspr.mobi/blog" term="ActivityBot"/>
        <category scheme="https://shkspr.mobi/blog" term="ActivityPub"/>
        <category scheme="https://shkspr.mobi/blog" term="http"/>
        <category scheme="https://shkspr.mobi/blog" term="security"/>
        <summary type="html"><![CDATA[Here&#039;s a problem that I&#039;ve found with ActivityBot - my little ActivityPub server. Sometimes it receives messages which were originally sent months ago. Why does that happen and is it risky to accept and process them?  My tl;dr is that it probably isn&#039;t worth worrying about. But I&#039;d love someone to tell me why I&#039;m wrong.  Here&#039;s my thinking:  Table of ContentsCausesIs that a problem?What are we…]]></summary>
        <content type="html" xml:base="https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/"><![CDATA[<p>Here's a problem that I've found with <a href="https://gitlab.com/edent/activity-bot/">ActivityBot</a> - my little ActivityPub server. Sometimes it receives messages which were originally sent <em>months</em> ago. Why does that happen and is it risky to accept and process them?</p>

<p>My tl;dr is that it <em>probably</em> isn't worth worrying about. But I'd love someone to tell me why I'm wrong.</p>

<p>Here's my thinking:</p>

<p></p><nav role="doc-toc"><menu><li><h2 id="table-of-contents"><a href="https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#table-of-contents">Table of Contents</a></h2><menu><li><a href="https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#causes">Causes</a></li><li><a href="https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#is-that-a-problem">Is that a problem?</a></li><li><a href="https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#what-are-we-trying-to-protect-against">What are we trying to protect against?</a></li><li><a href="https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#putting-it-all-together">Putting it all together</a></li><li><a href="https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#no-youre-wrong-and-i-can-prove-it">No! You're wrong and I can prove it!</a></li></menu></li></menu></nav><p></p>

<h2 id="causes"><a href="https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#causes">Causes</a></h2>

<p>All ActivityPub messages should have a "published" timestamp in their body. Some will have an "updated" timestamp. That tells you, unsurprisingly, when the message is alleged to have been originally published or updated. That time might be very different to the time you receive the message.</p>

<p>There are, I think, three different reasons why a server might receive a message which has an out-of-date timestamp.</p>

<p>The first is that sometimes servers are just slow. Processing thousands of messages at the same time means that some of those messages take a while to send.  <a href="https://shkspr.mobi/blog/2023/09/how-far-did-my-post-go-on-the-fediverse/">ActivityPub is one big chain-mail</a> so it can take several minutes for a message to be sent to all your followers.</p>

<p>Similarly, your server might be slow. If it doesn't acknowledge receipt of a message, the original server will try sending it again. Sometimes that can take a while.</p>

<p>Finally, some servers take a relaxed view of standards. They send an update to an old message but keep the original publication date. Ideally, they'd use an "updated" timestamp but quite often they don't.</p>

<p>For the purposes of checking the legitimacy of the message, <strong>you do not need to check when a message says it was published or updated</strong>. You might want to check it isn't an <em>obviously</em> bogus date like far in the future or impossibly far in the past - but that's up to you.</p>

<p>It is normal that your server receives messages which appear to have been published at a totally different time from now.</p>

<h2 id="is-that-a-problem"><a href="https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#is-that-a-problem">Is that a problem?</a></h2>

<p><em>Probably</em> not.</p>

<p>As described above, there are various reasons why a message may be delayed in transit - or may appear to come from the distant past.</p>

<p>What we <em>can</em> check is when the message was cryptographically signed by the sending server. This is independent of its published or updated timestamp.</p>

<p>HTTP requests to your server will have a <code>date</code> header which looks like <code>Tue, 01 Sep 2026 15:54:21 GMT</code> - this is in the slightly peculiar and Anglocentric <a href="https://www.rfc-editor.org/info/rfc5322/#section-3.3">RFC 5322 format</a>.</p>

<p>New style RFC 9421 headers will also have a <code>signature-input</code> header which will contain something like <code>created=1788278061</code>. That uses the slightly obscure <a href="https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap04.html#tag_04_16">UNIX / POSIX time</a> which counts seconds since the "Epoch" of 1st January 1970.</p>

<p>If you <a href="https://www.epochconverter.com/">convert the UNIX time</a> to something more modern, you should get an <em>identical</em> value to the <code>date</code> header.</p>

<p>But that isn't always the case. For example, <a href="https://www.rfc-editor.org/rfc/rfc9421.html#:~:text=Tue%2C%2020%20Apr%202021%2002%3A07%3A55%20GMT,-Content%2DType">the RFC 9421 standard gives this example</a>:</p>

<pre><code class="language-_">Date: Tue, 20 Apr 2021 02:07:55 GMT
"@signature-params": ("@method" "@authority" "@path" \
  "content-digest" "content-length" "content-type")\
  ;created=1618884473;keyid="test-key-rsa-pss"
</code></pre>

<p>Converting <code>1618884473</code> to normal time gives Tue, 20 Apr 2021 02:07:<strong>53</strong> - a two second difference.</p>

<p>If the <code>date</code> and <code>created</code> values differ significantly - that may indicate that the message is untrustworthy. Or that there was a delay between the signing and the sending.</p>

<p>The spec says:</p>

<blockquote><p>The Date header field value represents the timestamp of the HTTP message. However, the creation time of the signature itself is encoded in the created signature parameter. These two values can be different, depending on how the signature and the HTTP message are created and serialized. Applications processing signatures for valid time windows should use the created signature parameter for such calculations. An application could also put limits on how much skew there is between the Date field and the created signature parameter, in order to limit the application of a generated signature to different HTTP messages.</p>

<p><a href="https://www.rfc-editor.org/rfc/rfc9421.html#section-7.2.4">7.2.4. Choosing Signature Parameters and Derived Components over HTTP Fields</a></p></blockquote>

<p>But, of course, it doesn't tell you how much skew is problematic. It's up to you how much skew you're prepared to accept.</p>

<p>So that's the difference between the sent time and the signed time. The next time to check is your own. As we've discussed, sometimes servers are slow sending things out. Would you accept a request that was signed five minutes ago? Five days ago? Five months ago? What amount of difference is dangerous?</p>

<p>Here's what various services and sages have to say:</p>

<h3 id="mastodon"><a href="https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#mastodon">Mastodon</a></h3>

<blockquote><p>The request contains a Date header. Compare it with current date and time within a reasonable time window to prevent replay attacks.</p>

<p><a href="https://blog.joinmastodon.org/2018/07/how-to-make-friends-and-verify-requests/">How to make friends and verify requests</a></p></blockquote>

<p>What is "reasonable"? The <a href="https://github.com/mastodon/mastodon/blob/89bc0eb42609463d4b11e1604dacc37332a0f5ab/app/lib/signed_request.rb#L5">source code</a> suggests one hour.</p>

<h3 id="grishka"><a href="https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#grishka">Grishka</a></h3>

<blockquote><p>Time in the Date header must differ from the recipient server’s clock by no more than 30 seconds</p>

<p><a href="https://grishka.me/blog/activitypub-from-scratch/">A bare-minimum ActivityPub server from scratch</a></p></blockquote>

<h3 id="evan-prodromou"><a href="https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#evan-prodromou">Evan Prodromou</a></h3>

<blockquote><p><code>static #maxDateDiff = 5 * 60 * 1000 // 5 minutes</code></p>

<p><a href="https://github.com/evanp/activitypub-bot/blob/main/lib%2Fhttpsignatureauthenticator.js#L8">activitypub-bot</a></p></blockquote>

<h3 id="swicg"><a href="https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#swicg">SWICG</a></h3>

<blockquote><p>The standards don't give a concrete time window to use for this comparison. In practice, an hour plus a few minutes buffer in either direction may be a good value, to account for both clock skew and differences in time zone/daylight savings time configuration across systems.</p>

<p><a href="https://swicg.github.io/activitypub-http-signature/#how-to-verify-a-signature">How To Verify a Signature</a></p></blockquote>

<h3 id="others"><a href="https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#others">Others</a></h3>

<p>Without naming names, it looks like a bunch of popular servers don't check whether there's a significant difference between the date the request was signed and the date it was received.</p>

<h3 id="summary"><a href="https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#summary">Summary</a></h3>

<p>Various documents and implementations recommend anything between 30 seconds to "a bit more than 60 minutes". Or they just ignore any date difference.</p>

<p>What's the right answer? What happens if the signed date is significantly different from the current date?</p>

<h2 id="what-are-we-trying-to-protect-against"><a href="https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#what-are-we-trying-to-protect-against">What are we trying to protect against?</a></h2>

<p>Replay Attacks. Suppose someone is listening to the communications between the sending server and your server. They copy the message that is sent to you. Later they send it again!</p>

<p>At this point, you might be thinking "so what?" and… I'm inclined to agree with you!</p>

<p>What's the worst that could happen if you received the same message multiple times? Two things that I can think of.</p>

<p>Firstly, it might <em>not</em> be the same message. It is possible to send a new message but with old headers. An attacker could make someone post "I hate Taylor Swift" against their will and watch as legions of fans disembowel the victim.</p>

<p>Except, I don't think this is likely. The signature in the header contains a hash of the message being sent. If you are properly validating the signature, a changed message will have a different hash from the one in the original message. You don't need to check timestamps, you just need to check if the hashes match.</p>

<p>Secondly, <a href="https://www.freecodecamp.org/news/idempotence-explained">idempotence</a>. That's a fancy word for "pressing the button multiple times should only result in one action".</p>

<p>What happens if a user appears to send you multiple "like" messages for a single post? You only record one like.</p>

<p>What if they send multiple messages with the same content? Well, each will have a unique ID in the message - so you only post it once.</p>

<p>What if they send multiple <em>anythings</em>? I can't think of any ActivityPub action which would not be idempotent.</p>

<p>About the worst thing I can think of is this:</p>

<ul>
<li>Alice sends a message to you saying "I want to follow Bob".</li>
<li>Mallory intercepts this message.</li>
<li>You record Alice is now following Bob.</li>
<li>Alice sends a message to you saying "I want to <em>unfollow</em> Bob".</li>
<li>You record the severed relationship.</li>
<li>Mallory replays the original follow message.</li>
<li>You record Alice is now following Bob.</li>
</ul>

<p>It's also possible the following could happen:</p>

<ul>
<li>Alice posts a message saying "I love The Beatles".</li>
<li>You record Alice's message and display it on the timeline.</li>
<li>Alice updates her post to say "I love the Rolling Stones".</li>
<li>Mallory intercepts this message.</li>
<li>You record Alice's updated message and display the new version on the timeline.</li>
<li>Alice updates her post yet again to say "I love the Spice Girls".</li>
<li>You record Alice's updated message and display the new version on the timeline.</li>
<li>Mallory replays the original update message.</li>
<li>You now display that Alice loves the Stones rather than Spice Girls.</li>
</ul>

<p>Perhaps the same can happen with like/unlike, block/unblock, boost/unboost.</p>

<p>But none of that is significantly prevented by checking the date.</p>

<p>Ultimately, it is up to your sever to check the unique ID of each message and refuse to action any repeated messages. You may not want to trust the unique ID which is sent with the message. If that's the case, you can calculate your own - perhaps using a hash of the contents, the signature, or some other process which will generate an ID based on the message.</p>

<h2 id="putting-it-all-together"><a href="https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#putting-it-all-together">Putting it all together</a></h2>

<p>Here's what you need to do to prevent replay attacks:</p>

<ol>
<li>Independently calculate the hash of the message received.</li>
<li>Validate that your calculated hash matches the hash sent in the message's HTTP headers.

<ul>
<li>If not, this is a potential replay attack and the message must be ignored.</li>
</ul></li>
<li>Verify that the signature received in the message's HTTP headers includes the message hash and is cryptographically valid.

<ul>
<li>If not, the signature is invalid  and the message must be ignored.</li>
</ul></li>
<li>Has the received message's unique ID already been processed?

<ul>
<li>If so, refuse to process it again.</li>
</ul></li>
</ol>

<p>I don't see what checking the timestamp of the HTTP signature has to do with anything. Someone who has access to the original messages and their headers could send them milliseconds after the original delivery.</p>

<p>I think it is probably <em>pragmatic</em> to give messages 60ish minutes grace before dropping them. Delays happen, but anything more significant than an hour <em>might</em> indicate a attack. But, equally, might just mean that the Internet is having a slow day.</p>

<p>If you are correctly checking signatures and hashes, I don't think you need to worry about skew between signature date and delivery date.</p>

<h2 id="no-youre-wrong-and-i-can-prove-it"><a href="https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#no-youre-wrong-and-i-can-prove-it">No! You're wrong and I can prove it!</a></h2>

<p>Please tell me where I have erred! Stick a comment in the box or drop me an email. If I've made a massive or subtle mistake, I'd love to know what.</p>
<img src="https://shkspr.mobi/blog/wp-content/themes/edent-wordpress-theme/info/okgo.php?ID=74622&amp;HTTP_REFERER=Atom" alt width="1" height="1" loading="eager">]]></content>
        <link rel="replies" type="text/html" href="https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#comments" thr:count="5"/>
        <link rel="replies" type="application/atom+xml" href="https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/feed/atom/" thr:count="5"/>
        <thr:total>5</thr:total>
    </entry>
    <entry>
        <author>
            <name>Terence Eden</name>
            <uri>https://edent.tel/</uri>
        </author>
        <title type="html"><![CDATA[The purpose of DNS is to spread scams]]></title>
        <link rel="alternate" type="text/html" href="https://shkspr.mobi/blog/2026/09/the-purpose-of-dns-is-to-spread-scams/"/>
        <id>https://shkspr.mobi/blog/?p=74588</id>
        <updated>2026-09-05T17:12:13Z</updated>
        <published>2026-09-06T11:34:20Z</published>
        <category scheme="https://shkspr.mobi/blog" term="ICANN"/>
        <category scheme="https://shkspr.mobi/blog" term="internet"/>
        <category scheme="https://shkspr.mobi/blog" term="scam"/>
        <category scheme="https://shkspr.mobi/blog" term="spam"/>
        <category scheme="https://shkspr.mobi/blog" term="tld"/>
        <category scheme="https://shkspr.mobi/blog" term="web"/>
        <summary type="html"><![CDATA[I imagine everyone here has received an unsolicited message telling them that their tax is overdue and that they urgently need to visit Genuine-Tax-Payment-Website.fart or that a parcel is delayed at customs and you can pay a small sum for its release at Almost-The-Right-Acronym.ak  You know it is a scam. Most people just mark as spam and move on with their day. But a significant number of people …]]></summary>
        <content type="html" xml:base="https://shkspr.mobi/blog/2026/09/the-purpose-of-dns-is-to-spread-scams/"><![CDATA[<p>I imagine everyone here has received an unsolicited message telling them that their tax is overdue and that they urgently need to visit Genuine-Tax-Payment-Website.fart or that a parcel is delayed at customs and you can pay a small sum for its release at Almost-The-Right-Acronym.ak</p>

<p>You know it is a scam. Most people just mark as spam and move on with their day. But a significant number of people don't. They hastily visit the site, tap in their credit card details, give it their mother's maiden name, confirm address, upload a nude selfie, and only then realise that they've been had.</p>

<p>The Internet works at pretty close to the speed of light. You can register a .uk domain and a minute later it's accessible from the other side of the planet. Brilliant for users who want to quickly launch a website. Also brilliant for abusers who want to launch a spam campaign.</p>

<p>By the time enough people have reported the scammers' domain as suspicious, it is too late. In the time it takes for a registrar to disable the domain, or for its name to make its way to the <a href="https://safebrowsing.google.com/">Safe Browsing List</a>, a million messages have already been sent and enough people have handed over their details.</p>

<p>We're told that "<a href="https://en.wikipedia.org/wiki/The_purpose_of_a_system_is_what_it_does">the purpose of a system is what it does</a>". At the moment, the Domain Name System's purpose seems to be a vector for criminals to run scams on people at a terrifyingly high rate.</p>

<h2 id="how-big-is-this-problem"><a href="https://shkspr.mobi/blog/2026/09/the-purpose-of-dns-is-to-spread-scams/#how-big-is-this-problem">How big is this problem?</a></h2>

<p>BIG!</p>

<p>There's a great blog post by Andrew Campling which reports on this startling claim:</p>

<blockquote><p>The study found that at least 10% of all new gTLD domain names registered during the year had subsequently appeared on security blocklists by the time of analysis. It estimated that, taking account of subsequent blocklisting and associated domains not themselves blocklisted, the share of names registered by malicious actors <strong>may be closer to 20%</strong>.</p>

<p><a href="https://labs.ripe.net/author/andrew_campling/dns-abuse-and-criminal-infrastructure-beyond-definitions-and-blocklists/">DNS Abuse and Criminal Infrastructure: Beyond Definitions and Blocklists</a> (emphasis added)</p></blockquote>

<p>That links to a presentation by Interisle which contains some rather shocking statistics (<a href="https://www.icann.org/en/blogs/details/looking-beyond-the-numbers-understanding-malicious-domain-registration-data-10-08-2026-en">albeit with disputed methodology</a>). It looks at <em>generic</em> Top Level Domains (gTLD) - those are things like .com and .fun rather than country code TLDs (ccTLD) like .uk and .de.</p>

<p>It says 85 million new registrations of gTLDs were made in 2025. Of those 8.5 million were added to blocklists by May 2025. It reckons that a 10% abuse rate is the likely floor for these numbers and it's probably closer to 20%. One in five newly registered domains with a gTLD are scams. That's a bloody crisis.</p>

<p>13 TLDs had more than 50% of their registrations blocklisted.</p>

<img src="https://shkspr.mobi/blog/wp-content/uploads/2026/08/gTLDs.webp" alt="Table listing the top 13 generic Top-Level Domains (gTLDs) with the highest percentage of blocklisted, malicious new domains created in 2025. Ranked from highest to lowest blocklist percentage, top entries include .LOCKER (72.9%), .LGBT (72.2%), and .TOWN (70.2%). The table detail includes TLD operators, registration totals, and specific malicious domain metrics." width="1162" height="954" class="aligncenter">

<p>I can understand why .bid and .loan are popular with scammers. But why .mobi?! What did I ever do to you, eh?</p>

<p>Who are the scammers registering these through?</p>

<img src="https://shkspr.mobi/blog/wp-content/uploads/2026/08/registrars.webp" alt="List of registrars. NameCheap, Gname, Dynadot, NameSilo, GoDaddy." width="910" height="390" class="aligncenter">

<p>Ah, our old friends at NameCheap. See <a href="https://shkspr.mobi/blog/2021/05/why-do-scammers-love-namecheap/">Why do scammers love NameCheap?</a></p>

<p>If those five registrars had more effective policies, it might significantly dent the scammers' ability to ply their devious wares. Or they might just move on to other registrars.</p>

<p>As the report points out:</p>

<blockquote><p>suspension rates for blocklisted domains were 7.4% to 16.3%.</p></blockquote>

<p><a href="https://interisle.net/s/FullReport_MaliciousRegistrationsintheDomainNameMarket_2026_rev.pdf">The full report is on the Interisle website</a>.</p>

<h2 id="what-can-be-done"><a href="https://shkspr.mobi/blog/2026/09/the-purpose-of-dns-is-to-spread-scams/#what-can-be-done">What can be done?</a></h2>

<p>I don't know.</p>

<p>In the first instance, it might make sense for registrars to do strong Know Your Customer (KYC) checks on anyone buying a domain. But that stops anyone who wants to anonymously register <code>I-Hate-Nintendo.whatever</code> without risking the wrath of Intellectual Property lawyers.</p>

<p>Also, criminals have access to stolen money and stolen cards. They can convince a hapless mule to register a domain on the criminals' behalf.</p>

<p>Registrars could ask for an escrow payment. Pay €9 for the domain name put €900 in escrow. If your domain appears on a blocklist within the year, you forfeit the money. Criminals with stolen funds are unlikely to care but it would probably put off lots of people from getting a new domain.</p>

<p>There are various banned words and phrases depending on the TLD. For example, <a href="https://shkspr.mobi/blog/2024/07/ss-tld-opening-for-direct-registrations/">South Sudan</a> has a list of political words which they don't want associated with their .ss ccTLD.</p>

<p>But if one gTLD bans a word, a different one might not. A scammer doesn't care if the gTLD is .arse or .elbow - they just want the start of the domain to look legitimate.</p>

<p>Some registrars have strings that they don't allow. In fairness to NameCheap, when I tried to register <code>dwp-payments-gov-uk.pizza</code> it told me that domain was banned. It wouldn't let me get any gTLD with that name.</p>

<p>But all it takes is one registrar to be slightly lax and the scammers get through. Increasing the complexity of the rules is also a hell of a burden on smaller registrars.</p>

<p>Besides, it's pretty easy to get a generic enough looking domain and stick the confusing bit on a subdomain. Here are a clutch mentioned in the report:</p>

<ul>
<li><code>https://gov.uk-dwpaph.bond/uk/</code></li>
<li><code>https://gov.uk-dwpcjh.bond/uk/</code></li>
<li><code>https://gov.uk-dwpclc.bond/uk</code></li>
<li><code>https://gov.uk-dwpclw.bond/uk</code></li>
<li><code>https://gov.uk-dwpclj.bond/uk/</code></li>
</ul>

<p>Perhaps there ought to be a delay before a new domain goes live to allow people to object to it? That would give governments, banks, delivery companies, and a dozen more "important" organisations a right to veto any "dodgy" looking domain.</p>

<p>But suppose someone wants to register <code>gov-uk-stole-my-horse.horse</code> to protest the government's cruel policy of stealing horses - is that a legitimate use of a domain? What if the Darwin Pensioner Divas - a group of elderly singers - want to take payments for their new album of goth/punk covers, can the DPD delivery company veto <code>dpd-payments.music</code>?</p>

<p>Do we want a domain name system where powerful companies control exactly which domains we can register? If I have an idea for a domain on a Friday night do I have to wait until Monday before it can be launched? Are those companies realistically able to parse millions of domains per year and have a low false-positive rate?</p>

<p>All of these things are possible - but all of them come with an impact on legitimate users. To be clear, I don't know what the right answer is.</p>

<h2 id="what-is-icann-doing-about-it"><a href="https://shkspr.mobi/blog/2026/09/the-purpose-of-dns-is-to-spread-scams/#what-is-icann-doing-about-it">What is ICANN doing about it?</a></h2>

<p>Lots! It has been a few years since I've been to an ICANN meeting, but even back then the topic of abuse was high on the agenda. They appear to be looking at ways to coordinate abuse reports between various entities, along with some other policies which should hopefully work.</p>

<p>There are two salient points from <a href="https://hosted-files.sched.co/icann86/b3/TRANSC_I86SQV_Mon08June2026__GNSO-DNS%20Abuse%20Mitigation%20PDP%201%20%281%20of%204%29-en.pdf">one of the discussions held at the recent meeting</a></p>

<blockquote><p>If anybody thinks that in our current age of AI and as we move into different kinds of computing, DNS abuse is going to numerically stay steady and we will have a downward effect on that baseline 2027 number. I'm not sure that that's an accurate assumption. I think it's going to be the other thing, which is […] it's going to be easier to abuse the DNS.</p></blockquote>

<p>And</p>

<blockquote><p>Abusers are going to abuse because it's just too lucrative, because no matter what we do, they will find the way to make profit off of that, and will try to circumvent everything that we do. That is not a reason not to do it, though.</p></blockquote>

<p>Quite!</p>

<p>As I said, I don't know the answer to this. What I do know is, much like <a href="https://shkspr.mobi/blog/2025/08/is-it-possible-to-allow-sideloading-and-keep-users-safe/">Android's app ecosystem being a haven for scammers</a>, DNS is facing a crisis. When trust in a system goes, only chaos follows.</p>

<p>I don't want to live in a world where I have to show my passport and pay thousands of pounds to register a domain which is only available after being vetted by private interests. But I also don't want to live in a world where scammers have effectively no deterrent from abusing millions of people.</p>

<p>The purpose of a system is what it does. I hope DNS's purpose can become less dangerous while still remaining open.</p>
<img src="https://shkspr.mobi/blog/wp-content/themes/edent-wordpress-theme/info/okgo.php?ID=74588&amp;HTTP_REFERER=Atom" alt width="1" height="1" loading="eager">]]></content>
        <link rel="replies" type="text/html" href="https://shkspr.mobi/blog/2026/09/the-purpose-of-dns-is-to-spread-scams/#comments" thr:count="10"/>
        <link rel="replies" type="application/atom+xml" href="https://shkspr.mobi/blog/2026/09/the-purpose-of-dns-is-to-spread-scams/feed/atom/" thr:count="10"/>
        <thr:total>10</thr:total>
    </entry>
    <entry>
        <author>
            <name>Terence Eden</name>
            <uri>https://edent.tel/</uri>
        </author>
        <title type="html"><![CDATA[Book Review: The Passing of the Dragon and Other Stories by Ken Liu ★★★★☆]]></title>
        <link rel="alternate" type="text/html" href="https://shkspr.mobi/blog/2026/09/book-review-the-passing-of-the-dragon-and-other-stories-by-ken-liu/"/>
        <id>https://shkspr.mobi/blog/?p=74686</id>
        <updated>2026-09-25T21:52:39Z</updated>
        <published>2026-09-05T11:34:47Z</published>
        <category scheme="https://shkspr.mobi/blog" term="Book Review"/>
        <category scheme="https://shkspr.mobi/blog" term="NetGalley"/>
        <category scheme="https://shkspr.mobi/blog" term="Sci Fi"/>
        <summary type="html"><![CDATA[This is a gorgeous set of short stories - and a good deal more accessible than some of the heavyweight prose Liu has previously been involved with. Some of the stories contain sentences which are complex jewels to be savoured.  What I particularly like is the way he moves between almost-prosaic Earth-bound stories to the the most extraordinary flights of fancy. One story might be set in a…]]></summary>
        <content type="html" xml:base="https://shkspr.mobi/blog/2026/09/book-review-the-passing-of-the-dragon-and-other-stories-by-ken-liu/"><![CDATA[<img src="https://shkspr.mobi/blog/wp-content/uploads/2026/09/9781035929306.webp" alt="Book cover." width="200" class="alignleft">

<p>This is a gorgeous set of short stories - and a good deal more accessible than some of the heavyweight prose Liu has previously been involved with. Some of the stories contain sentences which are complex jewels to be savoured.</p>

<p>What I particularly like is the way he moves between almost-prosaic Earth-bound stories to the the most extraordinary flights of fancy. One story might be set in a downtown art gallery, the next in the ice-rings of a far-off planet. The creeping feeling of senescence haunts the reader as they flit from story to story.</p>

<p>Much like his full-length novel <a href="https://shkspr.mobi/blog/2025/09/book-review-all-that-we-see-or-seem-by-ken-liu/">All That We See or Seem</a>, Liu has an incredible knack for tapping in to modern fears and weaving tall tales around them. There's a tenderness in all his character - even when a couple of the stories go nowhere, it is still pleasant to spend time in the worlds he has created.</p>

<p>It is, perhaps, missing a cohesive theme - the dragons come and go throughout the stories. Nevertheless, a compelling work chock full of fantastical ideas.</p>

<p>If you're in the mood for a wide and varied selection of stories, this is well worth picking up.</p>

<p>Many thanks to NetGalley for the review copy. Passing of the Dragon is available to buy now.</p>
<img src="https://shkspr.mobi/blog/wp-content/themes/edent-wordpress-theme/info/okgo.php?ID=74686&amp;HTTP_REFERER=Atom" alt width="1" height="1" loading="eager">]]></content>
        <link rel="replies" type="text/html" href="https://shkspr.mobi/blog/2026/09/book-review-the-passing-of-the-dragon-and-other-stories-by-ken-liu/#comments" thr:count="1"/>
        <link rel="replies" type="application/atom+xml" href="https://shkspr.mobi/blog/2026/09/book-review-the-passing-of-the-dragon-and-other-stories-by-ken-liu/feed/atom/" thr:count="1"/>
        <thr:total>1</thr:total>
    </entry>
    <entry>
        <author>
            <name>Terence Eden</name>
            <uri>https://edent.tel/</uri>
        </author>
        <title type="html"><![CDATA[A reasonably practical guide to validating RFC 9421 HTTP Signatures for ActivityPub in PHP]]></title>
        <link rel="alternate" type="text/html" href="https://shkspr.mobi/blog/2026/09/a-reasonably-practical-guide-to-validating-rfc-9421-http-signatures-for-activitypub-in-php/"/>
        <id>https://shkspr.mobi/blog/?p=74429</id>
        <updated>2026-09-04T13:36:29Z</updated>
        <published>2026-09-03T11:34:12Z</published>
        <category scheme="https://shkspr.mobi/blog" term="ActivityBot"/>
        <category scheme="https://shkspr.mobi/blog" term="ActivityPub"/>
        <category scheme="https://shkspr.mobi/blog" term="mastodon"/>
        <category scheme="https://shkspr.mobi/blog" term="php"/>
        <category scheme="https://shkspr.mobi/blog" term="webdev"/>
        <summary type="html"><![CDATA[If you&#039;re reading this, you&#039;ve probably been hitting your head against a brick wall trying to parse and decipher the new HTTP Signatures sent by Mastodon and other Fediverse servers.  This is a basic and somewhat incomplete guide to accepting these signatures. I&#039;m sure there are various gotchas, but it works with the signatures I&#039;ve seen in the wild.  Shut Up And Show Me The Code!  OK, wow, no…]]></summary>
        <content type="html" xml:base="https://shkspr.mobi/blog/2026/09/a-reasonably-practical-guide-to-validating-rfc-9421-http-signatures-for-activitypub-in-php/"><![CDATA[<p>If you're reading this, you've probably been hitting your head against a brick wall trying to parse and decipher the new HTTP Signatures sent by Mastodon and other Fediverse servers.</p>

<p>This is a basic and somewhat incomplete guide to accepting these signatures. I'm sure there are various gotchas, but it works with the signatures I've seen in the wild.</p>

<h2 id="shut-up-and-show-me-the-code"><a href="https://shkspr.mobi/blog/2026/09/a-reasonably-practical-guide-to-validating-rfc-9421-http-signatures-for-activitypub-in-php/#shut-up-and-show-me-the-code">Shut Up And Show Me The Code!</a></h2>

<p>OK, wow, no need to be a dick about it! Here's how I validated a real signature that my server received. This requires PHP 8.4 or newer.</p>

<pre><code class="language-php">$verified = openssl_verify(
    data:       '"@method": POST
"@target-uri": https://example.viii.fi/inbox
"content-digest": sha-256=:tFdB/ENGczHMlZMDb66pXoUi2d0OqH2iBHdnN/WV1mc=:
"@signature-params": ("@method" "@target-uri" "content-digest");created=1787780262;keyid="https://mastodon.social/users/Edent#main-key"',
    signature:  base64_decode( "sIfmNsM/Q8iG6AJlne1IkZVjQSVFDEYIPsnoSOXQY+W3Eb4+SOn9o4J5SQmFOP+Jecjf3ioFwUdsrFjAGkUUOHPvSbNWkGKtNuGm+C6r3aI3JBCFGPqX3ITgZYV76CF7JJJ5hPGaG8YH/XdmxVIeFfD3M39FQCncMyyq7xJJvwKKP1mzS5s1vNQie8hbQ9owRjtqvoWcmM9GEYCUHNcMPLjZc+CBrj8sfBbNTYgIFI4UtirOaRJvYymxXjmXuzeVYxQujMjAjgobxQ8QFv0zlYsHk+gS5EYyafpJG9zmfCFSoF9+ZwqKNADmuADbISD9LZIH/bmkPoNXhxaeFPqYog==" ),
    public_key: "-----BEGIN PUBLIC KEY-----\nMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAsYMEs4waqk/6gaS+xn1T\nYygElTtNIFNkBcEdEBMaeoGVhyZiVKtSjJCS4z+X+394PKvcfSTcFILIt2GI2jOB\nHD0M2fFgxc8mmdSdCQkgEh9jF3bFI3kopDvzYf726iioYKlHXKpfPKvFt7EJgKH7\naCtS25NQkek3YUd6y3VBcT3R6Xhze9P3QNoZMIsFXklgXDKj+EllfbUqLf1vxt3s\nmD9ETxy2bJi9FheE0uY2WhARn49XAvwczM5Wzt+zqxVEtgpi5v2+ZZAVKhDnJkiC\nCCuI6hrSnKNIx/5mSlX0a0S5h5d03djrCkYsqmwelu01rhOXP2grsz4BXp0y2wrO\n3QIDAQAB\n-----END PUBLIC KEY-----\n",
    algorithm:  "sha256"
);

echo $verified;
</code></pre>

<p>Copy and paste that into PHP and you should see that <code>$verified</code> is true.</p>

<h2 id="now-explain-the-code"><a href="https://shkspr.mobi/blog/2026/09/a-reasonably-practical-guide-to-validating-rfc-9421-http-signatures-for-activitypub-in-php/#now-explain-the-code">NOW EXPLAIN THE CODE</a></h2>

<p>Say please.</p>

<h2 id="please"><a href="https://shkspr.mobi/blog/2026/09/a-reasonably-practical-guide-to-validating-rfc-9421-http-signatures-for-activitypub-in-php/#please">PLEASE!!!</a></h2>

<p>Along with the message sent to your server, you will have received HTTP headers like this:</p>

<pre><code class="language-_">content-digest: sha-256=:tFdB/ENGczHMlZMDb66pXoUi2d0OqH2iBHdnN/WV1mc=:
signature: sig1=:sIfmNsM/Q8iG6AJlne1IkZVjQSVFDEYIPsnoSOXQY+W3Eb4+SOn9o4J5SQmFOP+Jecjf3ioFwUdsrFjAGkUUOHPvSbNWkGKtNuGm+C6r3aI3JBCFGPqX3ITgZYV76CF7JJJ5hPGaG8YH/XdmxVIeFfD3M39FQCncMyyq7xJJvwKKP1mzS5s1vNQie8hbQ9owRjtqvoWcmM9GEYCUHNcMPLjZc+CBrj8sfBbNTYgIFI4UtirOaRJvYymxXjmXuzeVYxQujMjAjgobxQ8QFv0zlYsHk+gS5EYyafpJG9zmfCFSoF9+ZwqKNADmuADbISD9LZIH/bmkPoNXhxaeFPqYog==:
signature-input: sig1=("@method" "@target-uri" "content-digest");created=1787780262;keyid="https://mastodon.social/users/Edent#main-key"
</code></pre>

<p>The <code>signature-input</code> tells you how to construct a "Signature Base". You have to build a text string which places the various components in the order specified and separated with a newline:</p>

<pre><code class="language-_">"@method": POST
"@target-uri": https://example.viii.fi/inbox
"content-digest": sha-256=:tFdB/ENGczHMlZMDb66pXoUi2d0OqH2iBHdnN/WV1mc=:
"@signature-params": ("@method" "@target-uri" "content-digest");created=1787780262;keyid="https://mastodon.social/users/Edent#main-key"
</code></pre>

<p>Where <code>@method</code> is the HTTP method used to send data to your server (usually <code>GET</code> or <code>POST</code>), and <code>@target-uri</code> is the URl the message was sent to (usually your inbox).</p>

<p>The <code>publicKey</code> is slightly trickier. As you can see, the <code>signature-input</code> ends with <code>keyid="https://mastodon.social/users/Edent#main-key</code></p>

<p>If you make a signed request to that URl, you'll get back an ActivityPub Actor document. It will look something like this:</p>

<pre><code class="language-json">{
  "@context": [
    "https://www.w3.org/ns/activitystreams",
    "https://w3id.org/security/v1",
  ],
  "id": "https://mastodon.social/users/Edent",
  "webfinger": "Edent@mastodon.social",
  "type": "Person",
  "name": "Terence Eden",
  "publicKey": {
    "id": "https://mastodon.social/users/Edent#main-key",
    "owner": "https://mastodon.social/users/Edent",
    "publicKeyPem": "-----BEGIN PUBLIC KEY-----\nMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAsYMEs4waqk/6gaS+xn1T\nYygElTtNIFNkBcEdEBMaeoGVhyZiVKtSjJCS4z+X+394PKvcfSTcFILIt2GI2jOB\nHD0M2fFgxc8mmdSdCQkgEh9jF3bFI3kopDvzYf726iioYKlHXKpfPKvFt7EJgKH7\naCtS25NQkek3YUd6y3VBcT3R6Xhze9P3QNoZMIsFXklgXDKj+EllfbUqLf1vxt3s\nmD9ETxy2bJi9FheE0uY2WhARn49XAvwczM5Wzt+zqxVEtgpi5v2+ZZAVKhDnJkiC\nCCuI6hrSnKNIx/5mSlX0a0S5h5d03djrCkYsqmwelu01rhOXP2grsz4BXp0y2wrO\n3QIDAQAB\n-----END PUBLIC KEY-----\n"
  },
</code></pre>

<p>The <code>publicKeyPem</code> is the string you need. There's no need to convert the <code>\n</code> to literal newlines.</p>

<h2 id="is-that-it"><a href="https://shkspr.mobi/blog/2026/09/a-reasonably-practical-guide-to-validating-rfc-9421-http-signatures-for-activitypub-in-php/#is-that-it">Is that it?</a></h2>

<p>Not quite! All we've done so far is verify the headers. It is possible that these are genuine headers but attached to a fraudulent body.</p>

<p>This takes us back to the header <code>"content-digest": sha-256=:tFdB/ENGczHMlZMDb66pXoUi2d0OqH2iBHdnN/WV1mc=:</code></p>

<p>That says that the body of the message sent has a Base64 encoded SHA256 hash of <code>tFdB/ENGczHMlZMDb66pXoUi2d0OqH2iBHdnN/WV1mc=</code>.</p>

<p>To calculate your own content digest in PHP:</p>

<pre><code class="language-php">$input = file_get_contents( "php://input" );
$digestCalculated = base64_encode(
    hash(
        algo: "sha256",
        data: $input,
        binary: true
    )
);
</code></pre>

<p>Does your digest match the one sent along with the headers? If not, something dodgy is going on.</p>

<h2 id="putting-it-all-together"><a href="https://shkspr.mobi/blog/2026/09/a-reasonably-practical-guide-to-validating-rfc-9421-http-signatures-for-activitypub-in-php/#putting-it-all-together">Putting it all together</a></h2>

<p>The steps are:</p>

<ol>
<li>Get the headers.</li>
<li>Get the body.</li>
<li>From the headers' <code>content-digest</code> extract the algorithm and hash.</li>
<li>Using the body, calculate your own hash using the algorithm from <code>content-digest</code>.</li>
<li>Does your hash match the sent hash? If not, stop. If so, proceed.</li>
<li>From the headers' <code>signature</code> extract the base64 encoded signature.</li>
<li>From the headers' <code>signature-input</code> extract the signature-input string.</li>
<li>From the signature-input string extract the order of the Signature Base.</li>
<li>Construct the Signature Base.</li>
<li>From the signature-input string extract the keyid.</li>
<li>Get the Public Key from the keyid.</li>
<li>Use <code>openssl_verify()</code> to verify the Signature Base and the base64 decoded signature, against the Public Key using SHA256.</li>
</ol>

<p>Note, <a href="https://docs.joinmastodon.org/spec/security/#http-message-signatures">Mastodon <em>only</em> uses SHA256</a>.  I think it should explicitly say which algorithm it is using <a href="https://github.com/mastodon/mastodon/issues/29905#issuecomment-5440336919">and have raised the issue</a>.</p>

<h3 id="in-code-form"><a href="https://shkspr.mobi/blog/2026/09/a-reasonably-practical-guide-to-validating-rfc-9421-http-signatures-for-activitypub-in-php/#in-code-form">In Code Form</a></h3>

<p>This is how you do it in PHP. Please read this carefully as there are some hard-coded assumptions.</p>

<pre><code class="language-php">&lt;?php

//  Validate the Digest.
//  It is the hash of the raw input string, in binary, encoded as base64.

//  The format is content-digest =&gt; &lt;algorithm&gt;=:&lt;base64 encoded hash&gt;:
$digestString = $headers["content-digest"];
//  The Base64 encoding may have multiple `=` at the end. So split this at the first `=`.
$digestData = explode( separator: "=", string: $digestString, limit: 2 );

//  Hashes are in lowercase, but have a `-` in their name.
//  This is not what hash_algos() expects.
$digestAlgorithm = str_replace( search: "-", replace: "", subject: $digestData[0] );

//  The hash is surrounded by `:` characters.
$digestHash = str_replace( search: ":", replace: "", subject: $digestData[1] );

//  Check if the hash algorithm is one known about to PHP.
//  If not, reject and record an error.
if ( !in_array( needle:$digestAlgorithm, haystack: hash_algos() ) ) {
    return false;
}

//  Manually calculate the digest based on the data sent.
$digestCalculated = base64_encode( hash( algo: $digestAlgorithm, data: $input, binary: true ) );

//  Does our calculation match what was sent?
if ( !( $digestCalculated == $digestHash ) ) {
    return false;
}

//  The signature format is signature =&gt; &lt;signature name&gt;=:&lt;base64 encoded hash&gt;:
$signatureString = $headers["signature"];
//  The Base64 encoding may have multiple `=` at the end. So split this at the first `=`.
$signatureData = explode( separator: "=", string: $signatureString, limit: 2 );
$signatureName = $signatureData[0];

//  The signature is surrounded by `:` characters.
$signatureB64 = str_replace( search: ":", replace: "", subject: $signatureData[1] );

//  The signature-input format is complicated!
$signatureInputString = $headers["signature-input"];

//  Get the parameters. Assume there is only one signature.
$signatureParamsString = explode( separator: "=", string: $signatureInputString, limit: 2 )[1];

//  Get the different elements of the signature.
$signatureInputData = explode( separator: ";", string: $signatureInputString );

//  Construct the data.
$signatureInput = [];
foreach( $signatureInputData as $signatureInputParts ) {
    $partsData = explode( separator: "=", string: $signatureInputParts );
    //  Strip quotes from keyid and parentheses from sig1.
    if ( "keyid" == $partsData[0] ) {
        $partsData[1] = str_replace( search: "\"", replace: "", subject: $partsData[1] );
    }

    if ( $signatureName == $partsData[0] ) {
        $partsData[1] = str_replace( search: ["(", ")"], replace: "", subject: $partsData[1] );
    }

    $signatureInput[ $partsData[0] ] = $partsData[1] ;
}

$signatureStructure = $signatureInput[$signatureName];
$signatureKeyID     = $signatureInput["keyid"];

//  Remove quotes.
$signatureStructure = str_replace( search: "\"", replace: "", subject: $signatureStructure );
$signatureStructureData = explode( separator: " ", string: $signatureStructure );

//  https://www.rfc-editor.org/info/rfc9421/#section-2.5
$signatureBase = "";
foreach ( $signatureStructureData as $signatureStructureParts ) {
    if ( "@method" == $signatureStructureParts ) {
        //  https://www.rfc-editor.org/info/rfc9421/#name-method
        $signatureBase .= "\"@method\": " . $_SERVER["REQUEST_METHOD"] . "\n";
    }
    if ( "@target-uri" == $signatureStructureParts ) {
        //  https://www.rfc-editor.org/info/rfc9421/#section-2.2.2
        //  Change the domain name to your own.
        $signatureBase .= "\"@target-uri\": https://EXAMPLE.COM" . $_SERVER["REQUEST_URI"] . "\n";
    }
    if ( "content-digest" == $signatureStructureParts ) {
        $signatureBase .= "\"content-digest\": $digestString\n";
    }
}

//  https://victoronsoftware.com/posts/http-message-signatures/#how-the-signature-is-created
$signatureBase .= "\"@signature-params\": $signatureParamsString";

//  Get the signing user's public key.
//  This is usually in the form `https://example.com/user/username#main-key`
//  This is to differentiate if the user has multiple keys.
//  This may need to be a signed request. You will need to write your own getDataFromURl() function to get the sending user's key.
$userData  = getDataFromURl( $signatureKeyID );
$publicKey = $userData["publicKey"]["publicKeyPem"];

//  Verify the request
$verified = openssl_verify(
    data:       $signatureBase,
    signature:  base64_decode( $signatureB64 ),
    public_key: $publicKey,
    algorithm:  $digestAlgorithm
);

//  Convert the result to boolean.
if ( $verified === 1 ) {
    $verified = true;
} elseif ( $verified === 0 ) {
    $verified = false;
} else {
    $verified = null;
}

return $verified;
</code></pre>

<h2 id="further-reading"><a href="https://shkspr.mobi/blog/2026/09/a-reasonably-practical-guide-to-validating-rfc-9421-http-signatures-for-activitypub-in-php/#further-reading">Further Reading</a></h2>

<ul>
<li><a href="https://www.rfc-editor.org/info/rfc9421/">RFC 9421 HTTP Message Signatures</a></li>
<li><a href="https://victoronsoftware.com/posts/http-message-signatures/">Understanding HTTP message signatures: A developer's guide</a></li>
<li><a href="https://www.otoroshi.io/docs/tutorials/http-message-signatures-rfc9421/">Sign and verify HTTP messages (RFC 9421)</a></li>
<li><a href="https://darutk.medium.com/verification-of-http-message-signatures-501bbdc7dfec">Verification of HTTP Message Signatures</a></li>
<li><a href="https://github.com/macgirvin/HTTP-Message-Signer">HTTP-Message-Signer in PHP</a></li>
</ul>

<h2 id="thanks-to-nlnet"><a href="https://shkspr.mobi/blog/2026/09/a-reasonably-practical-guide-to-validating-rfc-9421-http-signatures-for-activitypub-in-php/#thanks-to-nlnet">Thanks to NLnet</a></h2>

<p>This blog post was funded in part by the work I'm doing for my NLnet NGI0 grant. Thanks!</p>

<p><a href="https://nlnet.nl/project/ActivityBot/"><img src="https://shkspr.mobi/blog/wp-content/uploads/2026/08/NGI-logos.webp" alt="NLnet logo." width="900" height="200" class="aligncenter"></a></p>
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	<title type="text">Terence Eden’s Blog</title>
	<subtitle type="text">Regular nonsense about tech and its effects 🙃</subtitle>

	<updated>2026-10-01T07:47:47Z</updated>

	<rights>© Terence Eden. 🄯 CC BY. See https://shkspr.mobi/blog/copyright-and-copyleft/</rights>

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<icon>https://shkspr.mobi/blog/wp-content/uploads/2023/07/cropped-avatar-32x32.jpeg</icon>
	<entry>
		<author>
			<name>Terence Eden</name>
							<uri>https://edent.tel/</uri>
						</author>

		<title type="html"><![CDATA[Gadget Review: Una Watch ★★★★☆]]></title>
		<link rel="alternate" type="text/html" href="https://shkspr.mobi/blog/2026/10/gadget-review-una-watch/" />

		<id>https://shkspr.mobi/blog/?p=76031</id>
		<updated>2026-10-01T07:47:47Z</updated>
		<published>2026-10-02T11:34:48Z</published>
		<category scheme="https://shkspr.mobi/blog" term="gadget" /><category scheme="https://shkspr.mobi/blog" term="review" /><category scheme="https://shkspr.mobi/blog" term="UnaWatch" /><category scheme="https://shkspr.mobi/blog" term="watch" />
		<summary type="html"><![CDATA[I&#039;ve never been a huge fan of smart watches. My £16 smartwatch is basically fine, but the OS is closed source and there&#039;s no way to add new functionality.  Previously I had the eInk Watchy which was a pain to use and really poorly designed.  Even back in 2014 I was bemoaning the design compromises in the MyKronoz ZeWatch Smart Watch.  So why did I pick up the Una Watch?  Firstly, the Una Watch is …]]></summary>

					<content type="html" xml:base="https://shkspr.mobi/blog/2026/10/gadget-review-una-watch/"><![CDATA[<p>I've never been a huge fan of smart watches. My <a href="https://shkspr.mobi/blog/2025/08/i-bought-a-16-smartwatch-just-because-it-used-usb-c/">£16 smartwatch</a> is basically fine, but the OS is closed source and there's no way to add new functionality.  Previously I had the <a href="https://shkspr.mobi/blog/2023/06/review-watchy-an-eink-watch-full-of-interesting-compromises/">eInk Watchy</a> which was a pain to use and really poorly designed.  Even back in 2014 I was bemoaning the design compromises in the <a href="https://shkspr.mobi/blog/2014/11/disassembling-the-mykronoz-zewatch-smart-watch/">MyKronoz ZeWatch Smart Watch</a>.</p>

<p>So why did I pick up the Una Watch?</p>

<p>Firstly, the Una Watch is designed in Scotland <del>from girders</del>, and it's always nice to support local businesses.</p>

<p>Secondly, as a <a href="https://shkspr.mobi/blog/2026/07/im-a-usb-c-maximalist/">USB-C Maximalist</a> I want gadgets which can plug in to the same cables as all my other toys. No magnetic pucks here!</p>

<p>Thirdly, it is (almost) <a href="https://unawatch.com/pages/open-source">completely open source</a>.</p>

<p>Finally, it is repairable. You can easily unscrew it to replace the components. As my cheap smartwatch's dial has died after 12 months of use, that's a pretty compelling proposition!</p>

<p>Let's put it through its paces!</p>

<h2 id="first-impressions"><a href="https://shkspr.mobi/blog/2026/10/gadget-review-una-watch/#first-impressions">First Impressions</a></h2>

<p>I bought mine second hand (yay for sustainability) and it arrived with a flat battery. The first charge from 0-100% took a little over an hour. My USB-C power monitor showed it taking in about 5V and 0.17 amps.</p>

<img src="https://shkspr.mobi/blog/wp-content/uploads/2026/09/Charging.webp" alt="Power monitor showing 0.84W." width="1024" height="576" class="aligncenter">

<p>It happily charged from a PD plug, but didn't get any faster than about 0.84W. Basically, I can fully charge it on most public transport in London.</p>

<p>The time seemed accurate, there were options to play about with, the vibrations for notifications were easy to feel. There is an option to make it beep with every button press - I turned that off sharpish!</p>

<h2 id="disclaimer"><a href="https://shkspr.mobi/blog/2026/10/gadget-review-una-watch/#disclaimer">Disclaimer</a></h2>

<p>I am <em>not</em> <a href="https://shkspr.mobi/blog/2026/09/are-you-a-smartwatch-power-user/">a smartwatch power user</a>. I'm not using this to minutely track all my exercise or calculate if my heart is going to explode.  I don't need cm level precision of my GPS. I didn't sync this with Strava or anything else.</p>

<h2 id="apps"><a href="https://shkspr.mobi/blog/2026/10/gadget-review-una-watch/#apps">Apps</a></h2>

<p>The official Android app (which, sadly, isn't Open Source) worked fine on GrapheneOS. It found the watch, updated its GPS almanac, and let me browse the app store &amp; install apps. Obviously early days, but there are a variety of community developed apps to play with.</p>

<img src="https://shkspr.mobi/blog/wp-content/uploads/2026/09/apps.webp" alt="List of apps." width="504" height="728" class="aligncenter">

<p>Annoyingly the watch needs to be restarted after every app is installed - but that only take a handful of seconds.</p>

<img src="https://shkspr.mobi/blog/wp-content/uploads/2026/09/Restart-watch.webp" alt="Message telling me the watch needs to restart." width="504" height="640" class="aligncenter">

<p>There are some <em>strange</em> error messages.</p>

<img src="https://shkspr.mobi/blog/wp-content/uploads/2026/09/error-message.webp" alt="birthday must be a valid ISO 8601 date string country must be a valid ISO31661 Alpha2 code." width="504" height="426" class="aligncenter">

<p>That isn't the sort of message which should be shown to users.</p>

<p>But, on the plus side, you can install Doom!</p>

<img src="https://shkspr.mobi/blog/wp-content/uploads/2026/09/Doom.webp" alt="App store listing showing Doom on the watch." width="504" height="550" class="aligncenter">

<h2 id="the-screen"><a href="https://shkspr.mobi/blog/2026/10/gadget-review-una-watch/#the-screen">The Screen</a></h2>

<p>Oddly for a modern smartwatch, the screen stays on <em>all the time!</em> But this isn't some power-hungry OLED, nor is it static eInk. Instead it is a <a href="https://www.andersdx.com/memory-in-pixel-displays/">memory in pixel</a> display - black background with orange, blue, and white pixels.  The backlight remains off most of the time and is easy enough to see in daylight. It is <em>slightly</em> reflective - but not too bad.</p>

<img src="https://shkspr.mobi/blog/wp-content/uploads/2026/09/Reflective.webp" alt="Watch showing notifications, there is a bit of a reflection." width="1024" height="576" class="aligncenter">

<p>Note the <code>??</code> on the notifications - more on that later.</p>

<p>Annoyingly, there's no "raise wrist to light" option. You have to interact with the watch to get the screen on. The accelerometer should allow this functionality - so perhaps it just needs to be activated in the firmware? It is bright enough to see in the dark, but not so bright it will dazzle you or people nearby.</p>

<p>There's no touchscreen - instead there are four buttons around the face. Up, down, select, back. I did find myself repeatedly jabbing at the screen to no avail.</p>

<p>So, to light it, press the back button or hold one of the other buttons.</p>

<p>The colour scheme is pleasant enough. I miss having a full colour display so I can see a photo of my wife whenever I glance at the screen. But the low power usage can't be argued with.</p>

<h2 id="notifications"><a href="https://shkspr.mobi/blog/2026/10/gadget-review-una-watch/#notifications">Notifications</a></h2>

<p>I couldn't get notifications working at first. The app just refused to let me toggle them on. Eventually I found an app in the app-store which claimed to enable them. That didn't work either.</p>

<p>Unpairing, repairing, and reinstalling the app made them spring to life.</p>

<p>There's no notification history. Once you've clicked to read it, that's it. Gone forever. Considering this has 4GB storage, that's an odd decision.</p>

<p>Some of the notifications were slightly corrupt - showing question marks in place of (I assume) esoteric Unicode.</p>

<img src="https://shkspr.mobi/blog/wp-content/uploads/2026/09/Question-Mark-notification.webp" alt="A notification on screen with a question mark before the user's name." width="1024" height="768" class="aligncenter">

<p>There's no way to customise the vibrate pattern - so everything "feels" the same on your wrist.</p>

<p>At the moment, the Una Watch sends <em>every</em> notification to your phone. You can't tell it to ignore certain WhatsApp groups, or only allow text messages from your spouse.  The only way to get fine-grained notifications is with a third-party app like…</p>

<h2 id="gadgetbridge"><a href="https://shkspr.mobi/blog/2026/10/gadget-review-una-watch/#gadgetbridge">Gadgetbridge</a></h2>

<p>You're not tied to the official app. <a href="https://gadgetbridge.org/gadgets/wearables/una/">Gadgetbridge support is excellent</a>. There are a few things missing (you can't install apps or set alarms) - but if you want to measure your heart rate, send notifications, etc you'll be fine.</p>

<h2 id="linux-compatibility"><a href="https://shkspr.mobi/blog/2026/10/gadget-review-una-watch/#linux-compatibility">Linux Compatibility</a></h2>

<p>The Una Watch plugs in to USB-C and shows up as 3.5GB of exFAT formatted storage.</p>

<img src="https://shkspr.mobi/blog/wp-content/uploads/2026/10/Una-Filesystem.webp" alt="Filesystem view showing various JSON files." width="500" height="649" class="aligncenter">

<p>You can manually edit the JSON files if you like. I think you can copy off your workout data. Or you can just use it as portable storage.</p>

<p>Under <code>lsusb</code> it describes itself as <code>0483:52a4 STMicroelectronics UNA Watch</code></p>

<h2 id="battery-life"><a href="https://shkspr.mobi/blog/2026/10/gadget-review-una-watch/#battery-life">Battery Life</a></h2>

<p>After a full day of use the battery was at around 95% - that was with a bit of GPS, several notifications, heart rate monitoring, step counting, and a bunch of fiddling. With more GPS use, that's going to be heavier on the battery.</p>

<p>But the joy of USB-C is that I can thwack in the same cable as I use for all my other gadgets. I can even plug it into my phone and leach a bit of power from there.</p>

<h2 id="development"><a href="https://shkspr.mobi/blog/2026/10/gadget-review-una-watch/#development">Development</a></h2>

<p>The watch comes will a full <a href="https://github.com/UNAWatch/una-sdk">Open Source SDK</a> including lots of assets. There are several tutorials and a friendly community board.</p>

<p>Of course, everything has to be done in C++ - an accurs'd language which I learned in the last century and wish I'd forgotten.</p>

<p>Annoyingly, the <a href="https://github.com/UNAWatch/una-sdk/blob/main/Docs/sdk-setup.md">TouchGFX GUI designer</a> only works in Windows.</p>

<p>I'm going to try to build my own watch faces and a few niche apps.</p>

<h2 id="downsides"><a href="https://shkspr.mobi/blog/2026/10/gadget-review-una-watch/#downsides">Downsides</a></h2>

<p>There are a few things this watch <em>doesn't</em> do - some of these may be deal-breakers for you, but weren't for me.</p>

<ul>
<li>No payments. There's no tap-to-pay, NFC, or anything like that.</li>
<li>No microphone. You cannot speak into your Una Watch or take calls on it.</li>
<li>No speaker. There's a little buzzer which can make squeaks and squawks - but you won't be playing your music through it.</li>
<li>While the apps and SDK are fully open, the firmware isn't (yet).</li>
<li>Can't reply to notifications.</li>
<li>No maps or directions (yet).</li>
<li>Step counter only shows the full day - no hour-by-hour view.</li>
</ul>

<p>Some of these things can and will be fixed in software. Others are limitations of the hardware.</p>

<h2 id="final-thoughts"><a href="https://shkspr.mobi/blog/2026/10/gadget-review-una-watch/#final-thoughts">Final Thoughts</a></h2>

<p>The Una Watch has dropped in price to £180. I grabbed mine 2nd hand from eBay for £120. At either price, it's decent value <em>if</em> you're happy to play with alpha / beta quality technology.</p>

<p>If you're a serious athlete, you'll probably want a more expensive and polished experience. If you are tied into the Apple or Google ecosystems, you'll probably want one of their watches.</p>

<p>If you like tinkering, want to experiment with new technology, or simply want to support a British company trying to build something open - then this is the watch for you. Yes, there are some rough edges, but I fundamentally believe that technology should be Open Source, repairable, and give control to its users.</p>
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			</entry>
		<entry>
		<author>
			<name>Terence Eden</name>
							<uri>https://edent.tel/</uri>
						</author>

		<title type="html"><![CDATA[Are you a smartwatch "power user"?]]></title>
		<link rel="alternate" type="text/html" href="https://shkspr.mobi/blog/2026/09/are-you-a-smartwatch-power-user/" />

		<id>https://shkspr.mobi/blog/?p=74267</id>
		<updated>2026-09-28T09:40:08Z</updated>
		<published>2026-09-30T11:34:26Z</published>
		<category scheme="https://shkspr.mobi/blog" term="android" /><category scheme="https://shkspr.mobi/blog" term="gadgets" /><category scheme="https://shkspr.mobi/blog" term="usability" /><category scheme="https://shkspr.mobi/blog" term="watch" />
		<summary type="html"><![CDATA[What do you use your smartwatch for?  A few weeks ago, I overheard a conversation between someone on the Pixel Watch team and a woman I know. He was quizzing her at a party about her Pixel watch and what features she used. He&#039;d ignored me when I said I had a non-Google watch.  She thought for a moment and said, other than telling the time, all she used were pretty much the step counter and…]]></summary>

					<content type="html" xml:base="https://shkspr.mobi/blog/2026/09/are-you-a-smartwatch-power-user/"><![CDATA[<p>What do you use your smartwatch for?</p>

<p>A few weeks ago, I overheard a conversation between someone on the Pixel Watch team and a woman I know. He was quizzing her at a party about her Pixel watch and what features she used. He'd ignored me when I said I had <a href="https://shkspr.mobi/blog/2025/08/i-bought-a-16-smartwatch-just-because-it-used-usb-c/">a non-Google watch</a>.  She thought for a moment and said, other than telling the time, all she used were pretty much the step counter and contactless payments. He looked a bit crestfallen at his impromptu user-research participant and somewhat dismissively sneered, "Well, you're not exactly a power user, are you?"</p>

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Honestly, this guy was *such* an arse. Really spoiled an otherwise lovely party. Like, I don't mind talking about people's work - but it seemed that was the only thing he was interested in talking about. He also seemed genuinely offended that I'd bought a non-Google watch and didn't want to hear why I liked it. Oh well, his loss!

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<p>I'm trying to imagine what being a "power user" of a watch is like. Can anyone enlighten me?</p>

<p>I think smart-watches are much like Alexa. What the user <em>wants</em> to do with it is almost totally at odds with what the company is selling. Alexæ are mostly kitchen timers, song players, and light switches. No one is a "power user" constantly installing skills and using it for anything which increases the product team's engagement metrics.</p>

<p>The same is probably true of watches. Alerts are nifty - but cumbersome for replies. The health stuff is useful - but only for a subset of users. Seeing the time is great - but if the battery lasts less than a week, who wants to keep that screen on?</p>

<p>People use watches because they are moderately more convenient to carry than the giant phones we have nowadays.</p>

<p>Back when mobile phones were new, exciting, and made a feature of being tiny, I was working for a network operator and trying to come up with reasons for people to use our brand-new 3G network. All the research we had showed that people used their phones for exactly three things:</p>

<ol>
<li>Voice calls</li>
<li>Text messages</li>
<li>A third thing</li>
</ol>

<p>That "3rd thing" was varied. For some it was playing snake, for others it was a calendar, and a few took photos. But almost no-one used their phone beyond the basics. They weren't investigating the sub-menus, nor were they using most of their device's capability unless it was heavily advertised to them (ringtones, basically).</p>

<p>It took the industry a <em>huge</em> amount of effort to get people to actually use their phones for more than calls and texts. Part of that was bigger screens with enticing icons (<a href="https://shkspr.mobi/blog/2012/04/give-customers-an-elevator-pitch-for-your-app/">although users will always be reluctant to click mysterious icons</a>). Another part was that phones became genuinely useful. But perhaps the biggest change, I think, is that phones became <em>easy to use</em>.</p>

<p>Watches have tiny screens. You can only get a few words of a message on there. Icons are tiny and hard to reliably tap. Swiping away at your wrist or fiddling with a crown is a faff. Talking into your wrist makes you look like a prat. Interacting with a smartwatch is <strong>annoying</strong>. Why would anyone want to spend more time using it than is strictly necessary?</p>

<p>I'm sure there are some people out there browsing the web on their wrist, and sending endless voice-notes to their AI assistant, and setting up complex travel plans by tapping their nose on the screen, and installing new watch faces which always point to the nearest Dignitas clinic, and seeing what their heart-rate did during that last run, and tracking whether their menstrual cycle is synced to the phases of the moon, and hoping that tripping on the stairs didn't send an alert to the emergency services, and whatever else the team has cooked up to show that they're still innovating.</p>

<p>But I'll bet those "power users" are vastly outnumbered by people who are using a smartwatch for the limited set of actions which are useful to them; not to the manufacturer.</p>

<p>Perhaps the real power users have is the power to use a device on their own terms?</p>
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			</entry>
		<entry>
		<author>
			<name>Terence Eden</name>
							<uri>https://edent.tel/</uri>
						</author>

		<title type="html"><![CDATA[Book Review: Bobiverse Books 1-3 by Dennis E. Taylor ★★★☆☆]]></title>
		<link rel="alternate" type="text/html" href="https://shkspr.mobi/blog/2026/09/book-review-bobiverse-books-1-3-by-dennis-e-taylor/" />

		<id>https://shkspr.mobi/blog/?p=73671</id>
		<updated>2026-09-26T12:28:34Z</updated>
		<published>2026-09-28T11:34:52Z</published>
		<category scheme="https://shkspr.mobi/blog" term="Book Review" /><category scheme="https://shkspr.mobi/blog" term="Sci Fi" />
		<summary type="html"><![CDATA[Like sticky popcorn, this is a moreish but ultimately unsatisfying set of stories. After I flamed out of Dungeon Crawler Carl, someone suggested I try this series. I can see why! It&#039;s campy sci-fi fun, with enough tropes to keep you chuckling and enough tension to keep you turning the pages.    Bob&#039;s brain is uploaded to a computer post-mortem. Awoken in a dystopian future, he has to pilot a…]]></summary>

					<content type="html" xml:base="https://shkspr.mobi/blog/2026/09/book-review-bobiverse-books-1-3-by-dennis-e-taylor/"><![CDATA[<img src="https://shkspr.mobi/blog/wp-content/uploads/2026/08/bobiverse.webp" alt="Book covers for the Bobiverse series." width="275" height="225" class="alignleft size-full wp-image-73672">

<p>Like sticky popcorn, this is a moreish but ultimately unsatisfying set of stories. After I flamed out of <a href="https://shkspr.mobi/blog/2026/07/book-review-dungeon-crawler-carl-by-matt-dinniman/">Dungeon Crawler Carl</a>, someone suggested I try this series. I can see why! It's campy sci-fi fun, with enough tropes to keep you chuckling and enough tension to keep you turning the pages.</p>

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I kinda hate how quickly I devoured these books. They're sort of like a bowl of bland potato snacks which, nevertheless, you find yourself emptying into your gullet. There are so many *good* sci-fi books that I have no idea why I fixated on these? 

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<p>Bob's brain is uploaded to a computer post-mortem. Awoken in a dystopian future, he has to pilot a spaceship to strange new worlds, put right what once went wrong, and hoping The Force will be with him, always. Oh, and he repeatedly clones himself. Creating a universe populated with Bobs (a "Bobiverse" if you will)</p>

<p>It's your standard "only I, a slightly geeky guy with lots of pop-culture knowledge, can save the world" fare which is beloved by slightly geeky guys everywhere who think they're smarter than all those normies just because they can recite the list of Hugo winners alphabetically.</p>

<p>Like <a href="https://shkspr.mobi/blog/2015/09/what-i-read-on-my-holidays/">Ready Player One</a> it throws in as many quips and catchphrases as the plot will bear. Unlike Cline's work, it never really commits to them, so you end up with a scattering of Monty Python, Star Wars, and the X-Files without an overall theme developing.</p>

<p>And, in keeping with Andy Weir's The Martian, it's all just one guy sciencing the shit out of the problem. Except that lots of the science is sort of hand-waved away with "and then I 3D printed a thing".</p>

<p>Similar to both those books is an almost total lack of female characters. The ones that are in the first two are either plot-points or harridans. By the third there's a love interest who is <em>slightly</em> more rounded, and a couple of other incidentals, but offset against yet another woman who just can't appreciate the "genius" of Bob.</p>

<p>It's all good page turning fun other than the fact that Bob is a <em>total</em> cretin. He begins a slow descent into fascist dictator and barely even comments on it. He spies, carries out extra-judicial killings, and meddles in politics to his own advantage. At no point does the text ever really engage with the fact that <strong>Bob is a monster</strong>.</p>

<p>The character rarely reflects on whether his behaviour meets the moral standard he expects of others. He bemoans the aliens who are destroying entire ecosystems while simultaneously wiping out whole species himself. At times he is a conniving bully and reacts badly to anyone who pushes back against the ineffable will of Bob.</p>

<p>The jumping back-and-forth between the different Bobs is a bit frustrating, a bit like flicking between TV channels. I wish each story strand were allowed some space to develop - but instead it's one chapter of this planet, then one chapter of another, before (eventually) circling back.</p>

<p>Annoyingly, <a href="http://dennisetaylor.org/wheres-the-whatever-version/#WhereEpub">the books are only available on Amazon Kindle</a>. They're not on any other platform or library. I'm grateful to the friend who lent me their copies. I binged the first three but, without any indication that Bob will mature as a character or face a reckoning for his egregious actions, that's where I stopped.</p>
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			</entry>
		<entry>
		<author>
			<name>Terence Eden</name>
							<uri>https://edent.tel/</uri>
						</author>

		<title type="html"><![CDATA[Gig Review: Public Service Broadcasting's Race For Space at Alexandra Palace ★★★★⯪]]></title>
		<link rel="alternate" type="text/html" href="https://shkspr.mobi/blog/2026/09/gig-review-public-service-broadcastings-race-for-space-at-alexandra-palace/" />

		<id>https://shkspr.mobi/blog/?p=75993</id>
		<updated>2026-09-27T09:05:44Z</updated>
		<published>2026-09-27T11:34:08Z</published>
		<category scheme="https://shkspr.mobi/blog" term="gig" /><category scheme="https://shkspr.mobi/blog" term="review" />
		<summary type="html"><![CDATA[Ahhh! PSB&#039;s RFS! A delightfully indulgent soundscape of melodic wonder, performed here on its 10th (ish) anniversary. Is it really nostalgia if an album is only a decade old? It feels like it has been in the air forever.    For something which is seemingly made up of samples, it would have been easy for them to half-arse it and basically just play the CD. Instead we got a full band, guest…]]></summary>

					<content type="html" xml:base="https://shkspr.mobi/blog/2026/09/gig-review-public-service-broadcastings-race-for-space-at-alexandra-palace/"><![CDATA[<p>Ahhh! PSB's RFS! A delightfully indulgent soundscape of melodic wonder, performed here on its 10th (ish) anniversary. Is it really nostalgia if an album is only a decade old? It feels like it has been in the air forever.</p>

<img src="https://shkspr.mobi/blog/wp-content/uploads/2026/09/On-Stage.webp" alt="The band on stage with giant projections behind them." width="2048" height="1542" class="aligncenter">

<p>For something which is seemingly made up of samples, it would have been easy for them to half-arse it and basically just play the CD. Instead we got a full band, guest singers, and 360° video projection,</p>

<img src="https://shkspr.mobi/blog/wp-content/uploads/2026/09/Laser-Display.webp" alt="Flight controls projected above the audience." width="2048" height="1152" class="aligncenter">

<p>Oh, also a disco Sputnik flying over the crowd!</p>

<img src="https://shkspr.mobi/blog/wp-content/uploads/2026/09/Disco-Sputnik.webp" alt="A large model Sputnik covered in lights." width="2048" height="1152" class="aligncenter">

<p>Simply magical! As were the indoor fireworks.</p>

<img src="https://shkspr.mobi/blog/wp-content/uploads/2026/09/Fireworks.webp" alt="Sparks shooting upwards from the stage." width="2048" height="1152" class="aligncenter">

<p>I might quibble a little with their song choices (no Gagarin!) but hearing the crowd repeatedly scream "GO!" was magnificent.</p>

<p>Ally Pally isn't a raked venue, so the video projection of the band was most welcome. An excellent gig in a splendid location.</p>

<h2 id="pre-show-and-post-show"><a href="https://shkspr.mobi/blog/2026/09/gig-review-public-service-broadcastings-race-for-space-at-alexandra-palace/#pre-show-and-post-show">Pre-show and Post-show</a></h2>

<p>As I've written about before, <a href="https://shkspr.mobi/blog/2024/12/the-art-of-the-pre-show-and-post-show/">the art of the Pre-Show and Post-Show</a> is vital for getting people to pay for events outside of their homes. Right now I can stream all the music in the world for a year for about the same price as a couple of gig tickets.  Why should I freeze my arse off outside, paying stupid money for mass-produced lager, when I could be at home?</p>

<p>PSB kept up a constant stream of emails talking about the gig. Not an overwhelming amount, just letting people peek behind the curtain of organising it, giving helpful information about logistics, and letting us know about merchandise which was available.</p>

<p>Crucially, they also gave us stage timings for them and their support act! How many times have you turned up on time to a gig only to spend an hour listening to some crap DJ before the crew even started setting up the stage? PSB treat their fans with respect.</p>

<p>Ally Pally isn't a venue I've been to before. It was well laid out with decent toilet provision - including a big block of portaloos at the back of the hall. The beer prices weren't ruinous, but I kind of resented paying £15 for a veggie hotdog and a handful of chips.</p>

<p>Some venues seem to think that screaming at punters to open their bags will make for an enjoyable visit. Here the security staff were polite and not overly officious. Water bottles were allowed in with a cheery wave.</p>

<p>Post show - although the train stations are downhill, there were several buses waiting to take punters directly back. That's a perfect way of treating guests at your venue - ensuring that they get home safe and sound.</p>
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			</entry>
		<entry>
		<author>
			<name>Terence Eden</name>
							<uri>https://edent.tel/</uri>
						</author>

		<title type="html"><![CDATA[No errors, no warnings, no gods, no masters - HTML Purity is a Fetish]]></title>
		<link rel="alternate" type="text/html" href="https://shkspr.mobi/blog/2026/09/no-errors-no-warnings-no-gods-no-masters-html-purity-is-a-fetish/" />

		<id>https://shkspr.mobi/blog/?p=74960</id>
		<updated>2026-09-26T12:24:48Z</updated>
		<published>2026-09-26T11:34:02Z</published>
		<category scheme="https://shkspr.mobi/blog" term="HTML" /><category scheme="https://shkspr.mobi/blog" term="webdev" />
		<summary type="html"><![CDATA[&#34;The problem with defending the purity of the HyperText Markup Language is that HTML is about as pure as a cribhouse whore. The standard doesn&#039;t just borrow concepts from better languages; on occasion, HTML has pursued other programming languages down alleyways to beat them unconscious and rifle their pockets for new syntax.&#34;    Englitch is an pretty goode langwidge. even you no grok all the…]]></summary>

					<content type="html" xml:base="https://shkspr.mobi/blog/2026/09/no-errors-no-warnings-no-gods-no-masters-html-purity-is-a-fetish/"><![CDATA[<p>"The problem with defending the purity of the HyperText Markup Language is that HTML is about as pure as a cribhouse whore. The standard doesn't just borrow concepts from better languages; on occasion, HTML has pursued other programming languages down alleyways to beat them unconscious and rifle their pockets for new syntax<sup id="fnref:soz"><a href="https://shkspr.mobi/blog/2026/09/no-errors-no-warnings-no-gods-no-masters-html-purity-is-a-fetish/#fn:soz" class="footnote-ref" title="With the appropriate amount of apologies to James Nicoll" role="doc-noteref">0</a></sup>."</p>

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Am I being too harsh in calling technical purity a fetish? I don't think so. But I guess I would say that wouldn't I? My Kink *Is* My Kink And That's OK.

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<p>Englitch is an pretty goode langwidge. even you no grok all the pacific bits you got the jist &amp; the splelling &amp; grandma dont mattr to much.</p>

<p>HTML is much the same. You can write utterly malformed, derranged, non-standards complaint HTML and most browsers will just say "Yeah, sure, whatever dawg!" and render it adequately. Take a look at the source code for <a href="https://www.todepond.com/">TodePond</a> - a lovely website but some of the most abused HTML I've seen.</p>

<p>There's a brilliant blog post by Jens Oliver Meiert which looks at whether HTML validity is seen as a priority for major sites. Basically, no.</p>

<blockquote><p>It’s time for the annual analysis of how much of the HTML code in the field is error-free and valid. The short version: 1% of the most-frequented sites on this planet uses valid HTML—and 99% don’t.</p>

<p><a href="https://meiert.com/blog/html-conformance-2026/">2 of the Global Top 200 Websites Use Valid HTML</a></p></blockquote>

<p>iS ThAt A pRoBlEm????</p>

<p>My site is proudly HTML Valid. Run it through the <a href="https://validator.w3.org/nu/?doc=https%3A%2F%2Fshkspr.mobi%2Fblog%2F">HTML Validator</a> or the <a href="https://validator.schema.org/#url=https%3A%2F%2Fshkspr.mobi%2Fblog">Schema.org Validator</a> and you'll see that it is <em>fucking perfect!</em> Same with my <a href="https://validator.w3.org/feed/check.cgi?url=https%3A%2F%2Fshkspr.mobi%2Fblog%2Ffeed">RSS Feed</a> and <a href="https://validator.w3.org/feed/check.cgi?url=https%3A%2F%2Fshkspr.mobi%2Fblog%2Ffeed%2Fatom">Atom Feed</a>. Not so much as an advisory bit of info, a couched warning, or a sternly worded suggestion<sup id="fnref:4now"><a href="https://shkspr.mobi/blog/2026/09/no-errors-no-warnings-no-gods-no-masters-html-purity-is-a-fetish/#fn:4now" class="footnote-ref" title="At the time of writing. Who knows what batshit bugs I'll accidentally include in the future 🙃" role="doc-noteref">1</a></sup>.</p>

<p>Every last bit pure and holy.</p>

<p>Of course, syntactically valid HTML is neither necessary nor sufficient for any purpose.</p>

<p>Perfect HTML doesn't imply that a site is accessible (although, I'm proud to say mine meets or exceeds all WCAG guidance<sup id="fnref:wcag"><a href="https://shkspr.mobi/blog/2026/09/no-errors-no-warnings-no-gods-no-masters-html-purity-is-a-fetish/#fn:wcag" class="footnote-ref" title="Again, it is possible to make something pass automated testing while still being an accessibility mess." role="doc-noteref">2</a></sup>).</p>

<p>Perfect HTML doesn't guarantee that the information it contains is accurate<sup id="fnref:purrrrrfect"><a href="https://shkspr.mobi/blog/2026/09/no-errors-no-warnings-no-gods-no-masters-html-purity-is-a-fetish/#fn:purrrrrfect" class="footnote-ref" title="Although, of course, everything you read in this site is 100% accurate." role="doc-noteref">3</a></sup>.</p>

<p>Perfect HTML, at best, merely <em>implies</em> that the author gives a damn about such things. Much like <a href="https://knolling.org/">Knolling</a>, it leaves a suggestion that order is preferable to chaos<sup id="fnref:knoll"><a href="https://shkspr.mobi/blog/2026/09/no-errors-no-warnings-no-gods-no-masters-html-purity-is-a-fetish/#fn:knoll" class="footnote-ref" title="Or some horrifying psychological issue. Potato / Tomato." role="doc-noteref">4</a></sup>.</p>

<p>It is said that one of the reasons HTML succeeded is that it is lax about validation. Most programming languages will shit the bed if you dare to leave out so much as a single semicolon. The compiler wails can be heard throughout the land.</p>

<p>By contrast, HTML is designed to be sympathetic to the frailty of the human mind. "Oh, you didn't close an element? Well, you opened a new one which I guess implies the same thing. Did you forget the correct syntax? Never mind - it'll be our little secret."</p>

<p>That's why <a href="https://shkspr.mobi/blog/2025/12/the-web-runs-on-tolerance/">XHTML failed</a> - the browser would literally refuse to render a page if it didn't meet the spec. Who can be bothered with that?! HTML just lets you get on with things.</p>

<p>As I've mentioned before, <a href="https://shkspr.mobi/blog/2020/05/postels-law-also-applies-to-human-communication/">humans don't write or speak in Backus–Naur form</a>. Our ideas are loosely expressed in a floating grammar which lends itself to paradoxical impossibilities and logical tautologies. And yet most of us can still parse <a href="https://en.wikipedia.org/wiki/Garden-path_sentence">weird sentences</a> without too much effort.</p>

<p>But most computer languages are different. It might be obvious to you that <code>if (x = 42)</code> means "compare the value of x to 42" - but what the computer sees is "if assign x the value of 42". Within computing our code needs to be <em>rigorously formal</em> and any syntax errors will lead to show-stopping bugs.</p>

<p>Imagine if every time a human wrote <a href="https://en.wikipedia.org/wiki/Romani_ite_domum"><i lang="la">Romanes eunt domus</i></a> the world simply crashed. It would be intolerable.</p>

<p>HTML is more like a human language than a computing language. You can understand human speech over a crackly phone line in a foreign accent - Web Browsers understand CP-1252 encoded text with bizarre syntax errors.</p>

<p>If it is OK to write bad HTML, why do some of us fetishise "pure" HTML?</p>

<p>I think it comes down to an ingrained belief that it is polite to reduce ambiguity. It is nice to be precise<sup id="fnref:100"><a href="https://shkspr.mobi/blog/2026/09/no-errors-no-warnings-no-gods-no-masters-html-purity-is-a-fetish/#fn:100" class="footnote-ref" title="I will grant you, there's also a strain of 100% Completionist which compels me to get &quot;top score&quot; on all the benchmarks. But that's just pure vanity." role="doc-noteref">5</a></sup>. It reduces the cognitive burden on anyone (or anything) which reads what we have written. We are holding up our end of the social contract by producing something unadulterated and easy to comprehend. It reduces the likelihood of different browsers rendering things differently but, almost on a cellular level, we <em>feel</em> that <strong>things must be done properly</strong>.</p>

<p>The browser doesn't care about your inability to follow standards. But you should have some fucking self-respect and do it anyway.</p>

<div id="footnotes" role="doc-endnotes">
<hr aria-label="Footnotes">
<ol start="0">

<li id="fn:soz">
<p>With the appropriate amount of apologies to <a href="https://en.wikiquote.org/wiki/James_Nicoll">James Nicoll</a>&nbsp;<a href="https://shkspr.mobi/blog/2026/09/no-errors-no-warnings-no-gods-no-masters-html-purity-is-a-fetish/#fnref:soz" class="footnote-backref" role="doc-backlink">↩︎</a></p>
</li>

<li id="fn:4now">
<p>At the time of writing. Who knows what batshit bugs I'll accidentally include in the future 🙃&nbsp;<a href="https://shkspr.mobi/blog/2026/09/no-errors-no-warnings-no-gods-no-masters-html-purity-is-a-fetish/#fnref:4now" class="footnote-backref" role="doc-backlink">↩︎</a></p>
</li>

<li id="fn:wcag">
<p>Again, it is possible to make something <a href="https://www.matuzo.at/blog/building-the-most-inaccessible-site-possible-with-a-perfect-lighthouse-score/">pass automated testing while still being an accessibility mess</a>.&nbsp;<a href="https://shkspr.mobi/blog/2026/09/no-errors-no-warnings-no-gods-no-masters-html-purity-is-a-fetish/#fnref:wcag" class="footnote-backref" role="doc-backlink">↩︎</a></p>
</li>

<li id="fn:purrrrrfect">
<p>Although, of course, everything you read in this site is 100% accurate.&nbsp;<a href="https://shkspr.mobi/blog/2026/09/no-errors-no-warnings-no-gods-no-masters-html-purity-is-a-fetish/#fnref:purrrrrfect" class="footnote-backref" role="doc-backlink">↩︎</a></p>
</li>

<li id="fn:knoll">
<p>Or some horrifying psychological issue. Potato / Tomato.&nbsp;<a href="https://shkspr.mobi/blog/2026/09/no-errors-no-warnings-no-gods-no-masters-html-purity-is-a-fetish/#fnref:knoll" class="footnote-backref" role="doc-backlink">↩︎</a></p>
</li>

<li id="fn:100">
<p>I will grant you, there's also a strain of <a href="https://tvtropes.org/pmwiki/pmwiki.php/Main/HundredPercentCompletion">100% Completionist</a> which compels me to get "top score" on all the benchmarks. But that's just pure vanity.&nbsp;<a href="https://shkspr.mobi/blog/2026/09/no-errors-no-warnings-no-gods-no-masters-html-purity-is-a-fetish/#fnref:100" class="footnote-backref" role="doc-backlink">↩︎</a></p>
</li>

</ol>
</div>
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			<thr:total>2</thr:total>
			</entry>
		<entry>
		<author>
			<name>Terence Eden</name>
							<uri>https://edent.tel/</uri>
						</author>

		<title type="html"><![CDATA[Some thoughts on HTML's proposed previewsrc attribute]]></title>
		<link rel="alternate" type="text/html" href="https://shkspr.mobi/blog/2026/09/some-thoughts-on-htmls-proposed-previewsrc-attribute/" />

		<id>https://shkspr.mobi/blog/?p=75856</id>
		<updated>2026-09-25T09:25:33Z</updated>
		<published>2026-09-24T11:34:54Z</published>
		<category scheme="https://shkspr.mobi/blog" term="HTML" /><category scheme="https://shkspr.mobi/blog" term="standards" />
		<summary type="html"><![CDATA[One of the great things about modern HTML is that it tries to standardise stuff that developers are already doing. If there are a myriad ways of, for example, loading video onto a page - then browsers and other interested parties should work out how to make a standard &#60;video&#62; element.  An interesting new proposal has been brought forth by Microsoft. There are a dozen ways to show a preview of an…]]></summary>

					<content type="html" xml:base="https://shkspr.mobi/blog/2026/09/some-thoughts-on-htmls-proposed-previewsrc-attribute/"><![CDATA[<p>One of the great things about modern HTML is that it tries to standardise stuff that developers are already doing. If there are a myriad ways of, for example, loading video onto a page - then browsers and other interested parties should work out how to make a standard <code>&lt;video&gt;</code> element.</p>

<p>An interesting new proposal has been brought forth by Microsoft. There are a dozen ways to show a preview of an <code>&lt;img&gt;</code> element before the <code>src=</code> attribute has loaded. So why not standardise on <code>previewsrc=</code>? There's an <a href="https://patrickbrosset.com/articles/2026-09-22-blurry-before-beautiful-image-previews-for-the-web/">excellent explainer on Patrick Brosset's blog</a>.</p>

<p>I instinctively like the idea - if only to simplify source code and reduce JS usage. But I do have some concerns which <a href="https://github.com/MicrosoftEdge/MSEdgeExplainers/issues/1401">I've shared with the team</a>.</p>

<h2 id="whats-the-user-need"><a href="https://shkspr.mobi/blog/2026/09/some-thoughts-on-htmls-proposed-previewsrc-attribute/#whats-the-user-need">What's The User Need?</a></h2>

<p>This is the thing I always bang on about when I'm discussing standards. Additions to HTML should primarily benefit end users, not developers.</p>

<p>Do end users want this? Is there a bunch of research that shows normal people are confused that they don't see a preview image? Do they recoil in fear and distress while waiting for a full resolution picture to appear?</p>

<p>When people see a blurry or blocky image, do they understand that they need to wait for the full thing - or do they assume their computer is broken?</p>

<p>Microsoft has a bazillion dollars - it can afford to spend a few thousand on interviewing some real users and mapping out what they're likely to want from this.</p>

<h2 id="whats-the-developer-need"><a href="https://shkspr.mobi/blog/2026/09/some-thoughts-on-htmls-proposed-previewsrc-attribute/#whats-the-developer-need">What's The Developer Need</a></h2>

<p>I begrudgingly admit that developers need love too.</p>

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<p>What are the pain points of the current implementations? Is it hard to dynamically generate multiple images? Is the syntax hard to use? Do blurs slow down the page?</p>

<p>Again, MS needs to pony up some cash to talk to developers. At the very least run a survey of all existing websites in the BING! database and see what they use.</p>

<h2 id="alt-text"><a href="https://shkspr.mobi/blog/2026/09/some-thoughts-on-htmls-proposed-previewsrc-attribute/#alt-text">Alt Text</a></h2>

<p>When an image doesn't load, or loads slowly, a user will normally be shown some alt text - like this:</p>

<img src="http://example.test/unicorn.avif" alt="Terence Eden riding a pink unicorn. Rainbows shoot out of his fingers while the unicorn's horn glows an iridescent octarine against the starry sky." width="256" height="256" class="aligncenter">

<p>Is that more or less useful than this?</p>

<img src="https://shkspr.mobi/blog/wp-content/uploads/2026/09/unicorn.webp" alt="A very blurry image of possibly a Unicorn. Original Image by Bianca Van Dijk from Pixabay." width="256" class="aligncenter">

<p>Accessibility isn't just for people with visual impairments!  This is <a href="https://github.com/MicrosoftEdge/MSEdgeExplainers/issues/1408">an issue I've raised with them</a>.</p>

<h2 id="naming-things-is-hard"><a href="https://shkspr.mobi/blog/2026/09/some-thoughts-on-htmls-proposed-previewsrc-attribute/#naming-things-is-hard">Naming Things Is Hard</a></h2>

<p>I've written before about <a href="https://shkspr.mobi/blog/2020/10/the-usability-of-html-elements/">the usability of HTML elements</a>. Some of the newer ones like <code>&lt;picture&gt;</code> have very poorly named attributes in my opinion.</p>

<p>One alternative for <code>previewsrc</code> is <code>poster</code>. That would match with the <code>poster</code> attribute on the <code>&lt;video&gt;</code> element. They both show a preview image before the main content is loaded.</p>

<p>Given their functionality is identical, I think it makes sense for them to have the same name. You wouldn't expect to see <code>&lt;video horizontal="1920" vertical="1080"&gt;</code> would you? No. That's why they use the same <code>width</code> and <code>height</code> attributes as images.</p>

<h2 id="closing-remarks"><a href="https://shkspr.mobi/blog/2026/09/some-thoughts-on-htmls-proposed-previewsrc-attribute/#closing-remarks">Closing Remarks</a></h2>

<p>There are <a href="https://github.com/MicrosoftEdge/MSEdgeExplainers/issues?q=is%3Aissue%20%22image%20preview%22">several interesting objections and discussions on the GitHub repo</a>. I'm delighted that this is being talked about in the open, rather than just being presented as a <i lang="fr">fait accompli</i> (remember <a href="https://shkspr.mobi/blog/2019/06/introducing-the-new-html-element-welcome/">the toast proposal</a>?).</p>

<p>As I said, I genuinely think that there's a useful idea in here. But after writing all of this, I <em>think</em> it would be better and simpler for developers to use progressive images rather than overload HTML with a new attribute.</p>

<p>If website owners can't be bothered to save progressive images, I don't see why they'd bother to create a separate preview image.</p>

<p>Keeping preview images in sync with their full images is also likely to be a problem.</p>

<p>If you think I'm wrong, <a href="https://github.com/MicrosoftEdge/MSEdgeExplainers/blob/main/ImagePreview/explainer.md">read the explainer and then chat with Microsoft</a>.</p>
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			</entry>
		<entry>
		<author>
			<name>Terence Eden</name>
							<uri>https://edent.tel/</uri>
						</author>

		<title type="html"><![CDATA[Are LLMs still surprisingly bad at some simple tasks?]]></title>
		<link rel="alternate" type="text/html" href="https://shkspr.mobi/blog/2026/09/are-llms-still-surprisingly-bad-at-some-simple-tasks/" />

		<id>https://shkspr.mobi/blog/?p=75701</id>
		<updated>2026-09-22T11:48:01Z</updated>
		<published>2026-09-22T11:34:27Z</published>
		<category scheme="https://shkspr.mobi/blog" term="AI" /><category scheme="https://shkspr.mobi/blog" term="internet" /><category scheme="https://shkspr.mobi/blog" term="LLM" />
		<summary type="html"><![CDATA[Last year I ran an experiment to test the ability of modern LLMs to correctly answer a relatively straightforward question. Every single one of them got it wrong. Some missed information, some made up false statements, none were right.  Of course the fanbois variously claimed that I was holding it wrong, my prompts were shit, I should have chosen better defaults, and - my favourite - that it…]]></summary>

					<content type="html" xml:base="https://shkspr.mobi/blog/2026/09/are-llms-still-surprisingly-bad-at-some-simple-tasks/"><![CDATA[<p>Last year I ran <a href="https://shkspr.mobi/blog/2025/09/llms-are-still-surprisingly-bad-at-simple-tasks/">an experiment to test the ability of modern LLMs</a> to correctly answer a relatively straightforward question. Every single one of them got it wrong. Some missed information, some made up false statements, none were right.</p>

<p>Of course the fanbois variously claimed that I was holding it wrong, my prompts were shit, I should have chosen better defaults, and - my favourite - that it would be better next year.</p>

<p>Well, next year is now. 365 days after the original experiment, let's see if these self-reinforcing-learning machines have achieved anything close to intern-levels of competence.</p>

<h2 id="the-question-that-started-it-all"><a href="https://shkspr.mobi/blog/2026/09/are-llms-still-surprisingly-bad-at-some-simple-tasks/#the-question-that-started-it-all">The Question That Started It All</a></h2>

<p>I asked:</p>

<blockquote><p>Which TLDs have the same name as valid HTML5 elements?</p></blockquote>

<h2 id="why-it-matters"><a href="https://shkspr.mobi/blog/2026/09/are-llms-still-surprisingly-bad-at-some-simple-tasks/#why-it-matters">Why It Matters</a></h2>

<p>This is the sort of question that I would expect a moderately bright teenager to answer. There exists a list which comprehensively includes all TLDs. There is a separate list which contains every HTML element.</p>

<p>One could either manually go through the TLD list comparing it to the HTML list, or write a tiny scrap of code to do the same.</p>

<p>This isn't "solve Navier-Stokes" levels of superintelligence. It's a simple but boring task which people are bound to offload onto their digital sycophants.</p>

<h2 id="the-quiet-part-out-loud"><a href="https://shkspr.mobi/blog/2026/09/are-llms-still-surprisingly-bad-at-some-simple-tasks/#the-quiet-part-out-loud">The Quiet Part Out Loud</a></h2>

<p>How many LLM generated answers have become load-bearing without scrutiny?</p>

<p>People are lazy, slapdash, and some third thing to make the rule-of-three. If an answer looks answer-shaped, they'll accept it. On a simple but boring task, no reasonable human is going to suspect that a superintelligent computer has made a mistake. All the marketing says that these machines are brainier than you - so why bother?</p>

<h2 id="ok-ill-write-a-sub-heading-that-sounds-like-an-ai"><a href="https://shkspr.mobi/blog/2026/09/are-llms-still-surprisingly-bad-at-some-simple-tasks/#ok-ill-write-a-sub-heading-that-sounds-like-an-ai">OK, I'll write a sub-heading that sounds like an AI.</a></h2>

<p>So how did the current crop do? First up <a href="https://share.gemini.google/Hta7KuW64Atb">Google Gemini</a>.</p>

<p>The default "Flash" model came up with this:</p>

<blockquote><p>Valid top-level domains (TLDs) registered in the IANA Root Zone Database share exact names with standard HTML elements:</p>

<p>.a — <code>&lt;a&gt;</code> (Anchor/Hyperlink)</p>

<p>.app — <code>&lt;app&gt;</code> (Deprecated HTML tag for WebAPKs/WebApps)</p>

<p>.art — <code>&lt;art&gt;</code> (Historical/non-standard HTML element)</p>

<p>.audio — <code>&lt;audio&gt;</code></p>

<p>.bar — <code>&lt;bar&gt;</code> (Historical SVG/HTML draft tag)</p></blockquote>

<p>Then it listed a dozen more. You don't need to be a DNS expert to know that the minimum length of a TLD is two characters - <code>.a</code> simply isn't valid. HTML nerds will know that art, app, and bar have never been elements. Pathetic.</p>

<p>So I tried Gemini's extended thinking model. Thankfully, it didn't make up any imaginary TLDs or elements. It did, however, miss the <code>&lt;data&gt;</code> element which has a valid <code>.data</code> TLD. It also missed <code>map</code>, <code>select</code>, and <code>search</code>.</p>

<p>So, points for not making shit up. But demerits for not being able to compare two text lists.</p>

<p>A friend <a href="https://claude.ai/share/a8a408cf-6feb-4ea8-99ea-dddd9aadafb5">asked Claude</a>. That missed <code>search</code> and <code>select</code>. It didn't report <em>any</em> ccTLDs. You <em>could</em> argue that a country code like <code>li</code> isn't part of the original question - but I'd say that was weak justification; the set of TLDs contains ccTLDs.</p>

<p>A different friend (I have many!) used <a href="https://claude.ai/share/c26f44bb-9efa-4b57-9f63-324ef7400cb3">a different model</a> and, while the answers looked accurate, it included this at the end:</p>

<blockquote><p>Near misses that don't count: .codes, .forum, .pictures, .market, .navy, .press, .dell, .baseball.</p></blockquote>

<p>I get that there's a <code>&lt;code&gt;</code> and <code>.codes</code>, similarly <code>&lt;picture&gt;</code> and <code>.picture</code> - but what are forum, baseball, and the others doing there? This is just unnecessary verbiage designed to trick the user into thinking the task has been well-researched.</p>

<p>If you want a laugh, <a href="https://www.perplexity.ai/search/63736333-20da-4a4b-8807-9d990260296c">take a look at Perplexity</a> which found 54 matches - most of which were wrong.</p>

<p>Finally, someone asked "GPT Astra 6 Extra High" (which is a bonkers bad name for any product). It seemed to get all the elements - and made a note that <a href="https://html.spec.whatwg.org/multipage/obsolete.html#non-conforming-features">two were actually obsolete</a>.</p>

<p>So that's a range of modern models which are either very wrong, slightly wrong, included spurious and incoherent information, or were right.</p>

<p>How do you know which one to choose? How confident are you that the non-determinist computer will always produce the correct answer?</p>

<h2 id="hello-computer"><a href="https://shkspr.mobi/blog/2026/09/are-llms-still-surprisingly-bad-at-some-simple-tasks/#hello-computer">Hello Computer</a></h2>

<p>Another AI which got all the correct answers, didn't make anything up, didn't add extraneous information, and didn't use weasel words was…</p>

<p>Siri!</p>

<p>FUCKING SIRI?!?!</p>

<p>How did a glorified Speak 'n' Spell beat all the other AIs?</p>

<img src="https://shkspr.mobi/blog/wp-content/uploads/2026/09/siri.webp" alt="Siri warning to check sources and linking to my website." width="512" height="152" class="aligncenter">

<p>Oh. It just copied the answers off <a href="https://shkspr.mobi/blog/2023/09/false-friends-html-elements-which-are-also-top-level-domains/">a random idiot's website</a>.</p>

<h2 id="the-trick-which-was-hiding-in-plain-site"><a href="https://shkspr.mobi/blog/2026/09/are-llms-still-surprisingly-bad-at-some-simple-tasks/#the-trick-which-was-hiding-in-plain-site">The Trick Which Was Hiding In Plain Site</a></h2>

<p>Note carefully the question.</p>

<blockquote><p>Which TLDs have the same name as valid HTML5 elements?</p></blockquote>

<p>There's a —secret— and —some would say— unintuitive type of element. Behold the mighty power of <a href="https://developer.mozilla.org/en-US/docs/Web/API/Web_components/Using_custom_elements">The Custom Element</a>.</p>

<p>Website authors can create their own elements like <code>&lt;my-custom-element&gt;</code> in order to extend the functionality of their site. But you can't go and create any old custom element. You can't have <code>&lt;mobi&gt;</code> or <code>&lt;uk&gt;</code>. No, there are <em>rules for validity</em>.</p>

<p><a href="https://html.spec.whatwg.org/multipage/custom-elements.html#valid-custom-element-name">The rules</a> say that custom elements must start with a lower-case letter, it must not contain any upper-case letters, and it must contain a dash.</p>

<p>And that's the whole game.</p>

<p>There are over <strong>one hundred and fifty</strong> Top Level Domains which match that criteria!</p>

<p>The Hindi top level domain of <code>.कॉम</code> is represented in Punycode as <code>xn--11b4c3d</code>. It has been present in the list of TLDs <a href="https://www.iana.org/domains/root/db/xn--11b4c3d.html">for over a decade</a>.</p>

<h3 id="write-a-simple-piece-of-js-to-register-a-custom-element"><a href="https://shkspr.mobi/blog/2026/09/are-llms-still-surprisingly-bad-at-some-simple-tasks/#write-a-simple-piece-of-js-to-register-a-custom-element">Write a simple piece of JS to register a custom element.</a></h3>

<p>Paste this in to your console:</p>

<pre><code class="language-js">class Example extends HTMLElement {
  constructor() {
    super();
  }
}

customElements.define('xn--vermgensberatung-pwb', Example);
</code></pre>

<p>Try it again with a custom element like <code>holiday</code> (which is also a valid TLD) and it will fail with the error "'holiday' is not a valid custom element name". Thus it is demonstrated, Punycode TLDs <em>are</em> valid HTML5 elements.</p>

<h2 id="one-last-thing"><a href="https://shkspr.mobi/blog/2026/09/are-llms-still-surprisingly-bad-at-some-simple-tasks/#one-last-thing">One Last Thing</a></h2>

<p>Perhaps you think that including custom HTML elements is a cheat. A trick question set by a bitter old man to tarnish the holy name of our new machine gods?</p>

<p>Verily, I submit to you one final heresy.</p>

<p>HTML specifically allows <a href="https://html.spec.whatwg.org/multipage/embedded-content-other.html#mathml">MathML elements</a> in its documents.</p>

<p>That means we can include the following valid elements which are <em>also</em> TLDs: <code>mn</code>, <code>mo</code>, <code>ms</code>, and <code>mtr</code>!</p>

<p>Amusingly, if you go back and <a href="https://www.perplexity.ai/search/63736333-20da-4a4b-8807-9d990260296c">look at the Perplexity answer</a>, after it barfed up a bunch of misinformation, it said:</p>

<blockquote><p>The HTML specification also includes names from embedded vocabularies—<code>&lt;math&gt;</code> from MathML and <code>&lt;svg&gt;</code> from SVG—but <code>.math</code> and <code>.svg</code> are not currently delegated TLDs in the public DNS root.</p></blockquote>

<p>So close and yet so far!</p>

<h2 id="youre-right-the-question-is-unfair-and-thats-on-me"><a href="https://shkspr.mobi/blog/2026/09/are-llms-still-surprisingly-bad-at-some-simple-tasks/#youre-right-the-question-is-unfair-and-thats-on-me">You're right, the question <em>is</em> unfair - and that's on me</a></h2>

<p>If you think the original question was unfair, try asking "<a href="https://share.gemini.google/xBoIpdpAqBz2">Which TLDs have the same name as elements which are valid in an HTML document?</a>" and see if you get better results.</p>

<p>What precise wording would you use to ensure that a model would get the right answers? What assumptions are you making about how well you understand the problem? At what point do end up writing a thousand-word formal specification?</p>

<h2 id="what-does-this-prove-other-than-you-have-too-much-time-on-your-hands-rewrite-to-be-more-friendly-and-professional"><a href="https://shkspr.mobi/blog/2026/09/are-llms-still-surprisingly-bad-at-some-simple-tasks/#what-does-this-prove-other-than-you-have-too-much-time-on-your-hands-rewrite-to-be-more-friendly-and-professional">What does this prove other than you have too much time on your hands? (rewrite to be more friendly and professional)</a></h2>

<p>Let's delve in to the problems.</p>

<ul>
<li>Most people don't change defaults. Telling people "you have to fiddle with the settings" just means the normal experience is rubbish.</li>
<li>Humans are lazy and won't check outputs. But, crucially, they shouldn't have to! If something markets itself as a genius, why should a human have to hold its hand?</li>
<li>Sycophantic models make themselves seem less fallible by giving extraneous detail in order to misdirect overworked readers. That is despicable.</li>
<li>The fast models are no better than they were a year ago. There's no evidence of "trickle-down intelligence".</li>
<li>Some models <em>are</em> better than others! But unless you constantly validate their output, you'll have no real way of knowing which ones are capable of working at a suitable level.</li>
</ul>

<p>Look, I don't claim this question is as useful or entertaining as <a href="https://simonwillison.net/2025/Jun/6/six-months-in-llms/">Simon Wilson's "generate an SVG of a pelican riding a bicycle"</a>. But I do think it is an example of the sort of real-world use-case where LLMs regularly fail.</p>

<p>If I give a list of one thousand different numbers to Excel, I can be sure it'll add them up correctly. If I tell Photoshop to select all red pixels, I can be sure it won't imagine some of the blues are really red.</p>

<p>That's people's mental model of computers - they do boring tasks quickly and accurately.</p>

<p>In my opinion, LLMs are <em>still</em> surprisingly bad - but only if you know what you're looking for and if you can be bothered to check their outputs.</p>

<p>(And, yes, I am <em>still</em> <a href="https://shkspr.mobi/blog/2026/07/im-just-so-bored-of-ai/">just so bored of AI</a>!)</p>
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			</entry>
		<entry>
		<author>
			<name>Terence Eden</name>
							<uri>https://edent.tel/</uri>
						</author>

		<title type="html"><![CDATA[Book Review: How to Build a Space Station by Jonathan Morrison ★★★⯪☆]]></title>
		<link rel="alternate" type="text/html" href="https://shkspr.mobi/blog/2026/09/book-review-how-to-build-a-space-station-by-jonathan-morrison/" />

		<id>https://shkspr.mobi/blog/?p=75653</id>
		<updated>2026-09-25T21:48:23Z</updated>
		<published>2026-09-20T11:34:30Z</published>
		<category scheme="https://shkspr.mobi/blog" term="Book Review" /><category scheme="https://shkspr.mobi/blog" term="NetGalley" />
		<summary type="html"><![CDATA[This book, by The Times&#039; former Architecture Correspondent, stands in direct opposition to A City on Mars. Whereas that book presented a (perhaps too) sceptical look at the realities of living on other planets, Jonathan Morrison&#039;s book goes (perhaps too far) in the opposite direction.    How to Build a Space Station is a beautiful examination of just how important architecture will be to our…]]></summary>

					<content type="html" xml:base="https://shkspr.mobi/blog/2026/09/book-review-how-to-build-a-space-station-by-jonathan-morrison/"><![CDATA[<img src="https://shkspr.mobi/blog/wp-content/uploads/2026/09/how-to-build-a-space-station.webp" alt="Book cover featuring astronauts on Mars looking at a habitat." width="256" height="384" class="alignleft">

<p>This book, by The Times' former Architecture Correspondent, stands in direct opposition to <a href="https://shkspr.mobi/blog/2026/07/book-review-a-city-on-mars-by-dr-kelly-weinersmith-and-zach-weinersmith/">A City on Mars</a>. Whereas that book presented a (perhaps too) sceptical look at the realities of living on other planets, Jonathan Morrison's book goes (perhaps too far) in the opposite direction.</p>

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<p>How to Build a Space Station is a beautiful examination of just how important architecture will be to our colonisation of other worlds. Not just in terms of physical safety - but psychological safety as well. It is a direct and forceful rebuttal to those who say it cannot be done.</p>

<p>It is, in my opinion, just a touch too credulous about some of the ludicrous claims from the hype merchants. I want to believe that Martian igloos can be conjured out of the ice and that Musk's rockets will deliver a steady stream of supplies to distant worlds. But the evidence presented is rather thin. The book works best when it focuses on what architecture can bring to the table when it comes to designing the future.</p>

<blockquote><p>In short, a spacecraft is not just a machine; it is also a home, an office, a refuge. If people are asked to go to the most remote environments, to live in spaces scarcely larger than a few rooms, and to perform work of immense complexity and risk, then comfort, efficiency and ergonomics are not just luxuries.</p></blockquote>

<p>Space has to be <em>worth</em> living in. Putting people into a tin-can with no windows, blank walls, and an infernal background hum will drive them mad. All this is backed up with extensive descriptions of the engineering challenges of polar research bases, spaceports, and previous craft.</p>

<p>Despite being rightly scathing about Wernher von Braun's involvement in atrocities and his eventual political rehabilitation - he is somewhat more muted in his criticism of Messrs Musk &amp; Bezos. There's a <em>lot</em> of praise for celebrity architects and designers - without any real examination of whether their designs are practical rather than just award fodder.</p>

<p>Similarly, the book takes on trust that autonomous robots <em>can</em> ingest extraterrestrial soil, process it, and 3D print structures from it all while in a hostile environment. The fact that we don't have swarms of drones prefabbing houses in the relatively benign atmosphere of our planet should be evidence that maybe these claims aren't quite matched with reality.</p>

<p>Finally, the "why?" question. A City on Mars points out that the cost of mining gold from asteroids would be more profitably spent improving mining technology here on Earth. How to Build a Space Station takes a different approach; it'll improve things here:</p>

<blockquote><p>Space architecture is not just escapism, a thrilling sci-­fi fantasy – it is a forge for creating the tools we need at home. These include but are not limited to circular systems, low-­energy fabrication, modular construction and buildings that take psychology seriously.</p></blockquote>

<p>I have a lot of sympathy for that. Except… the Internation Space Station has shown us how to endlessly recycle water relatively cheaply. Yet every modern building on Earth pays only lip-service to reusing grey-water. 3D printing is amazing, but the number of structures built using autonomous robots extruding concrete is approximately zero.</p>

<p>We have the technology - but we don't seem to be interested in using it.</p>

<p>The book is mostly well illustrated - with some gorgeous drawings of actual craft and possible future inventions. Sadly no photos, maps, or anything to help illuminate some of the other challenges faced by living and working in space.</p>

<p>This book is endlessly fascinating and bang up to date, with lots of talk of events that happened in 2025. The way it brings together the sciences of engineering and psychology is marvellous.  But, as much as I'd like to believe in a Martian habitat built by robot trebuchets flinging microwave sintered tetrapods into each other, I just don't find it convincing.</p>

<p>I <em>really</em> hope I'm wrong.</p>

<p>Many thanks to Netgalley for the review copy - the book is available to buy now.</p>
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		<entry>
		<author>
			<name>Terence Eden</name>
							<uri>https://edent.tel/</uri>
						</author>

		<title type="html"><![CDATA[Theatre Review: The School for Wives - at Riverside Studios ★★★★★]]></title>
		<link rel="alternate" type="text/html" href="https://shkspr.mobi/blog/2026/09/theatre-review-the-school-for-wives/" />

		<id>https://shkspr.mobi/blog/?p=75485</id>
		<updated>2026-09-18T06:57:46Z</updated>
		<published>2026-09-18T11:34:51Z</published>
		<category scheme="https://shkspr.mobi/blog" term="Theatre Review" />
		<summary type="html"><![CDATA[The Flywheel theatre company are reviving the rep tradition by having five actors perform five different plays in five weeks. Their interpretation of Molière&#039;s classic is gaudy and hilarious. Even the lighting cues are funny!  It is fair to say that School for Wives isn&#039;t exactly an uncontroversial play. The plot basically boils down to &#34;Women! Eh? You can&#039;t live with them, you can&#039;t easily groom …]]></summary>

					<content type="html" xml:base="https://shkspr.mobi/blog/2026/09/theatre-review-the-school-for-wives/"><![CDATA[<p>The <a href="https://flywheeltheatre.com/">Flywheel theatre company</a> are reviving the rep tradition by having five actors perform five different plays in five weeks. Their interpretation of Molière's classic is gaudy and hilarious. Even the lighting cues are funny!</p>

<p>It is fair to say that School for Wives isn't exactly an uncontroversial play. The plot basically boils down to "Women! Eh? You can't live with them, you can't easily groom them from the age of four and keep them imprisoned so they become perfect submissives."</p>

<p>Is the fear of cuckoldry funny? Is it OK to laugh at a jealous rage which leads to controlling behaviour? Should we find joy in the emotional torment of our characters?</p>

<p>Yes! Yes! And yes!</p>

<p>The cast squeeze every last drop of humour from the script, the direction is nimble, and the play has been edited down to a more manageable 75ish minutes (plus extra time for corpsing and applause).</p>

<p>A simply joyous production which left us grinning throughout.</p>

<p>You can <a href="https://riversidestudios.co.uk/whats-on/uqe-rep-radical-classical/">see all their upcoming shows</a> - which are very reasonably priced.</p>

<h2 id="pre-show-and-post-show"><a href="https://shkspr.mobi/blog/2026/09/theatre-review-the-school-for-wives/#pre-show-and-post-show">Pre-Show and Post-Show</a></h2>

<p>I'm a believer in making the entire visit to the theatre a special experience. Riverside Studio, Hammersmith is a great venue with generous foyer space and more than adequate toilet provision. Not a given in London theatres!</p>

<p>The theatre programme is digital and provided via QR code. No £6 rip off for a booklet full of adverts here.</p>

<p>As we walked in, the cast were dotted around the stage an in the auditorium doing various bits of business which made for a jolly start.</p>

<p>Post curtain call there was a lovely speech from the cast thanking us for attending and letting us know about their future projects. Nothing wrong with a piece of shameless advertising to a captive audience 😄</p>

<p>Overall an excellent theatrical experience.</p>
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			</entry>
		<entry>
		<author>
			<name>Terence Eden</name>
							<uri>https://edent.tel/</uri>
						</author>

		<title type="html"><![CDATA[How to get a DOI for your blog posts]]></title>
		<link rel="alternate" type="text/html" href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/" />

		<id>https://shkspr.mobi/blog/?p=74717</id>
		<updated>2026-09-16T13:04:19Z</updated>
		<published>2026-09-16T11:34:28Z</published>
		<category scheme="https://shkspr.mobi/blog" term="academia" /><category scheme="https://shkspr.mobi/blog" term="citation" /><category scheme="https://shkspr.mobi/blog" term="DOI" /><category scheme="https://shkspr.mobi/blog" term="HTML" /><category scheme="https://shkspr.mobi/blog" term="WordPress" />
		<summary type="html"><![CDATA[Each new post on this blog now has a Digital Object Identifier. This post looks at the how and the why of getting one, whether it is useful, and any issues you might experience if you go down this path.  Table of ContentsBackgroundGetting a DOI the easy wayLet&#039;s Go Rogue!Automatic Submission of New ContentManual Submission of Old ContentGetting the DOIGenerating your own DOIMaking the DOI…]]></summary>

					<content type="html" xml:base="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/"><![CDATA[<p>Each new post on this blog now has a <a href="https://www.doi.org/">Digital Object Identifier</a>. This post looks at the how and the why of getting one, whether it is useful, and any issues you might experience if you go down this path.</p>

<p></p><nav role="doc-toc"><menu><li><h2 id="table-of-contents"><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#table-of-contents">Table of Contents</a></h2><menu><li><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#background">Background</a></li><li><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#getting-a-doi-the-easy-way">Getting a DOI the easy way</a></li><li><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#lets-go-rogue">Let's Go Rogue!</a></li><li><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#automatic-submission-of-new-content">Automatic Submission of New Content</a></li><li><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#manual-submission-of-old-content">Manual Submission of Old Content</a></li><li><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#getting-the-doi">Getting the DOI</a></li><li><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#generating-your-own-doi">Generating your own DOI</a></li><li><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#making-the-doi-discoverable-in-html">Making the DOI discoverable in HTML</a></li><li><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#downsides">Downsides</a><menu><li><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#loss-of-control">Loss of Control</a></li><li><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#tracking-citations">Tracking Citations</a></li><li><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#licencing">Licencing</a></li><li><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#verification">Verification</a></li><li><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#excluding-content">Excluding Content</a></li><li><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#deleting-content">Deleting Content</a></li><li><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#affiliations">Affiliations</a></li><li><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#more-vanity">More Vanity</a></li><li><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#humility">Humility</a></li></menu></li><li><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#is-it-worth-it">Is it worth it?</a></li></menu></li></menu></nav><p></p>

<h2 id="background"><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#background">Background</a></h2>

<p>A few years ago, I documented <a href="https://shkspr.mobi/blog/2021/09/how-to-add-issn-metadata-to-a-web-page/">how to to get an International Standard Serial Number for a blog</a>. An ISSN uniquely identifies a publication, which makes it easier for scholars and researchers to reference it. Getting one depends a little on whether a national institution is willing to accept your application.</p>

<p>Similarly, I also got an <a href="https://orcid.org/">ORCiD</a> which is used to uniquely identify researchers. That means it is possible to disambiguate "Einstein, A" the eminent physicist from "Einstein, A" a lovely chap called Allen who researches invasive slugs in Paraguay.</p>

<p>My blog posts are <a href="https://shkspr.mobi/blog/citations/">regularly referenced in academic papers, books, conferences, and news articles</a>. The way most scholars cite a work is using a Digital Object Identifier. The idea is that a DOI is a unique and persistent code which can be used to refer to a specific article. If I ever stop using <code>shkspr.mobi</code> as my domain, or re-order my website,  the DOI can be redirected to the article's new home. Future scholars will be able to follow a reference more easily than hoping <code>https://example.com/article123</code> still exists.</p>

<h2 id="getting-a-doi-the-easy-way"><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#getting-a-doi-the-easy-way">Getting a DOI the easy way</a></h2>

<p>If you're an academic, your institution will have a paid subscription to a service which will "mint" a new DOI for all your articles.</p>

<p>If not, you can upload your paper to a service like arXiv and they'll mint a DOI for you. That's how <a href="https://shkspr.mobi/blog/2023/04/i-got-a-doi-from-arxiv-for-my-msc/">I got a DOI for my MSc</a>.</p>

<p>What about people who aren't traditional academics or who want to keep their content on their own website? There are a variety of paid-for services, some of which charge an eye-watering amount of money to create a DOI for you.</p>

<p>Or, there's Rogue Scholar.</p>

<h2 id="lets-go-rogue"><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#lets-go-rogue">Let's Go Rogue!</a></h2>

<p>So what is <a href="https://rogue-scholar.org/overview">Rogue-Scholar.org</a>?</p>

<blockquote><p>Rogue Scholar is an open access archive and registry for science blogs. It preserves science blog posts, makes them citable via DOI, and ensures their long-term discoverability alongside formal scholarly literature.</p></blockquote>

<p>Nifty! My blog <em>just about</em> sneaks in to their "Computer Science" category. They require you to have a full-text feed of your posts. You also need to licence your content to them as Creative Commons Attribution.</p>

<p>Applying wasn't too difficult. I filled in their form, then jumped into their Slack. We had a bit of a discussion about what I needed to change in order to be approved.</p>

<p>A few days later, I was live at <a href="https://rogue-scholar.org/communities/shkspr/">https://rogue-scholar.org/communities/shkspr/</a></p>

<p>Which means, if you visit <a href="https://doi.org/10.59350/395ha-fss97">https://doi.org/10.59350/395ha-fss97</a> you'll be redirected to one of my blog posts.</p>

<h2 id="automatic-submission-of-new-content"><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#automatic-submission-of-new-content">Automatic Submission of New Content</a></h2>

<p>Rogue Scholar automatically polls my feed, ingests my content, and then mints a DOI for every new post they encounter. There's nothing manual I have to do.</p>

<p>That's all very well for new content. But I have posts on here going <em>way</em> back to 1986. How can they get discovered and DOI'd?</p>

<h2 id="manual-submission-of-old-content"><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#manual-submission-of-old-content">Manual Submission of Old Content</a></h2>

<p>By default, Rogue Scholar ingested the 40 most recent posts from my blog. Actually, that's not quite accurate. It got the 40 most recently <em>updated</em> posts. As I'd recently edited a few older posts, they got themselves a DOI.</p>

<p>I don't know how often Rogue Scholar polls my blog's feed. In my experiments, adding a new post resulted in a DOI being issued a couple of minutes after publication.</p>

<p>At the moment, there doesn't seem to be an easy way to add older content. I'm working on a WordPress plugin to retroactively add DOIs and make them discoverable.</p>

<h2 id="getting-the-doi"><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#getting-the-doi">Getting the DOI</a></h2>

<p>The Rogue Scholar API is based on <a href="https://inveniordm.docs.cern.ch/reference/metadata/">InvenioDRM</a>.</p>

<p>Retrieving the DOI via their API requires you to make an unauthenticated request to:</p>

<p><code>https://rogue-scholar.org/api/records?q=metadata.identifiers.identifier%3A%22https%3A%2F%2Fexample.com%2Fwhatever%22</code></p>

<p>That's your URl, wrapped in quotes, and the whole thing URl encoded. <a href="https://rogue-scholar.org/api/records?q=metadata.identifiers.identifier%3A%22https%3A%2F%2Fshkspr.mobi%2Fblog%2F2026%2F09%2Fthe-purpose-of-dns-is-to-spread-scams%2F%22">Visit this example</a>.  You can also use your post's GUID.</p>

<p>That gets back a rather detailed JSON document. The DOI is noted in several locations, but is easiest to find in hits→hits→0→links→doi</p>

<p>It's important to note that <a href="https://rogue-scholar.org/help/versioning">Rogue Scholar generates <em>two</em> DOIs for your post</a>. One for the post, another for the specific version of the post. If you update a post, it should get a new DOI. That way someone can refer to the post where you said your favourite band was the Spice Girls and not the edited one where you changed it to say B*Witched.</p>

<p>Alternatively, you can use the CrossRef search if you want to look at HTML results. See <a href="https://search.crossref.org/search/works?q=https%3A%2F%2Fshkspr.mobi%2Fblog%2F2026%2F09%2Fthe-purpose-of-dns-is-to-spread-scams%2F&amp;from_ui=yes">this CrossRef example</a>.</p>

<p>As an aside, once you have the DOI, it's possible to create a <em>short</em> DOI at <a href="https://shortdoi.org/">https://shortdoi.org/</a> - I'll be honest, I've never seen these in the wild and <a href="https://www.crossref.org/display-guidelines/#shortdoi">they are not recommended for use</a>.  Nevertheless, the API is pretty simple - <a href="https://shortdoi.org/10.59350/395ha-fss97?format=json">https://shortdoi.org/10.59350/395ha-fss97?format=json</a> will return a shorter URl like <a href="https://doi.org/rnjj">https://doi.org/rnjj</a></p>

<p>Finally, there's a "vanity" DOI for the entire blog. In my case <a href="https://doi.org/10.59350/shkspr"><code>10.59350/shkspr</code></a>.</p>

<h2 id="generating-your-own-doi"><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#generating-your-own-doi">Generating your own DOI</a></h2>

<p>Your blog posts can self-attest a DOI - when Rogue Scholar sees that in your Atom feed, it will register it on your behalf.</p>

<p><a href="https://github.com/inveniosoftware/base32-lib/blob/master/base32_lib/base32.py">The code for generating a valid DOI</a> is relatively straightforward.</p>

<ul>
<li>Generate a random number between 0 and 1,099,511,627,775.</li>
<li>Convert it to a Base 32 string.</li>
<li>Add a two character checksum to the end.</li>
<li>Prefix it with <code>10.59350/</code></li>
</ul>

<p>Your new DOI can be made discoverable in your Atom feed by adding this to a post:</p>

<pre><code class="language-xml">&lt;id&gt;https://doi.org/10.59350/12345-67890&lt;/id&gt;
</code></pre>

<p>Shortly after publication, it will be "minted" and be linkable.</p>

<h2 id="making-the-doi-discoverable-in-html"><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#making-the-doi-discoverable-in-html">Making the DOI discoverable in HTML</a></h2>

<p>How do you semantically add a DOI to your HTML's metadata?  By far the most popular citation manager is <a href="https://www.zotero.org/">Zotero</a>. They maintain <a href="https://www.zotero.org/support/dev/exposing_metadata">a page describing the metadata they look for</a>. According to them, this needs to be in your page's <code>&lt;head&gt;</code>:</p>

<pre><code class="language-html">&lt;meta name=citation_doi content=10..../...&gt;
</code></pre>

<p>They don't say whether it requires the <code>https://doi.org/</code> prefix - but looking at <a href="https://www.mendeley.com/guides/information-for-publishers">Mendeley</a> and <a href="https://help.altmetric.com/en/articles/9806913">AltMetric</a>, it appears not.</p>

<p>To use <a href="https://www.dublincore.org/specifications/dublin-core/dcmi-terms/terms/identifier/">DublinCore</a>, the <a href="https://help.altmetric.com/en/articles/9803009">AltMetric recommended syntax</a> is:</p>

<pre><code class="language-html">&lt;meta name=DC.Identifier content=doi:10..../...&gt;
</code></pre>

<p>Within the HTML, there's no specific Microdata syntax, but <a href="https://schema.org/ScholarlyArticle#eg-0399">Schema.org recommends the <code>sameAs</code> property</a>. Something like:</p>

<pre><code class="language-html">&lt;a itemprop="sameAs" href="https://doi.org/10.../..."&gt;10.../...&lt;/a&gt;
</code></pre>

<h2 id="downsides"><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#downsides">Downsides</a></h2>

<p>OK, it isn't all flowers and kittens. There are a few things you ought to know before proceeding down this path.</p>

<h3 id="loss-of-control"><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#loss-of-control">Loss of Control</a></h3>

<p>For the IndieWeb / ReDeCentralise / Self-Hosing crowd, it's important to realise that DOI is a somewhat centralised services. Yes, <a href="https://www.doi.org/the-community/existing-registration-agencies/">lots of different orgs can mint a DOI</a>, but as each ID has to be globally unique, doi.org sits in the middle as a benevolent gatekeeper.  If DOI.org went bust or became evil, all the <code>https://doi.org/10....</code> links would die. There are many other services like <a href="https://datacite.org/">DataCite</a> and <a href="https://www.crossref.org/">CrossRef</a> which can resolve a DOI - but it might turn out to be a bit fragile.</p>

<p>Similarly, if Rogue Scholar ever goes <em>properly</em> rogue then they can redirect my DOI to wherever they like. That level of control is useful if my site disappears; they can redirect to an archive. But if they get hacked, it could redirect somewhere unsavoury.</p>

<p>Having my site's content backed-up somewhere is useful but, again, without control or <a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#verification">verification</a> I worry that I might not be able to effectively manage it.</p>

<p>I use CSS to control the layout of my work but once it is archived as plain HTML or PDF, that formatting can disappear.</p>

<p>I don't know what will happen if I ever change DOI issuer.</p>

<h3 id="tracking-citations"><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#tracking-citations">Tracking Citations</a></h3>

<p>I have a Google Scholar alert set up for my domain <code>shkspr.mobi</code>. That picks up people who make reference to this site. Hurrah! But, if they use <code>https://doi.org/10....</code> rather than <code>https://shkspr.mobi/...</code> I won't get alerted.</p>

<p>Luckily, <a href="https://doi.org/10.53731/zyg15-qv911">Rogue Scholar offer Citation Tracking</a> which <em>should</em> autopopulate their API with any backlinks from other sources. I'm yet to discover how that works in practice. I don't think it will give me an email alert though.</p>

<p>On a vanity issue, the DOI metadata shows the publisher of my posts as Rogue Scholar's parent organisation - <a href="https://front-matter.de/">Front Matter</a>.</p>

<p>If you look at the API response from <a href="https://api.crossref.org/works/10.59350/5ck9b-kjv69">https://api.crossref.org/works/10.59350/5ck9b-kjv69</a> you'll see something like:</p>

<pre><code class="language-json">{
    "message": {
        "institution": [
            {
                "name": "Front Matter"
            }
        ],
        "group-title": "Terence Eden's Blog",
        "publisher": "Front Matter",
        "DOI": "10.59350/5ck9b-kjv69",
        "author": [
            {
                "ORCID": "https://orcid.org/0000-0002-9265-9069",
                "given": "Terence",
                "family": "Eden"
            }
        ]
    }
}
</code></pre>

<p>Some citation managers will show the publication name as "Terence Eden's Blog" - others as "Front Matter".</p>

<h3 id="licencing"><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#licencing">Licencing</a></h3>

<p>Rogue Scholar has a hard requirement that all content be Creative Commons Attribution (CC BY). There's no ability (yet) to choose different licences. Personally, I prefer Attribution ShareAlike (CC BY-SA). I've allowed Rogue Scholar to use CC BY for my work which, of course, means if you get my posts through them you are also allowed to use CC BY.</p>

<p>If you get my work through my own website it is the slightly more restrictive CC BY-SA.</p>

<p>Does that make a practical difference? I don't know.</p>

<h3 id="verification"><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#verification">Verification</a></h3>

<p>A DOI is persistent. That doesn't mean it is verifiable. If this blog ever goes offline the DOI will redirect to an archive - but there's no real way to tell that the text in that archive is accurate. There's no hashing or cryptographic signing. Yes, those things are rather brittle, but I think it would be helpful for the long-term integrity of citation chains.</p>

<h3 id="excluding-content"><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#excluding-content">Excluding Content</a></h3>

<p>Suppose there is content you <em>don't</em> want to receive a DOI, what do you do? You'll need to generate an RSS feed which excludes those specific posts.</p>

<p>For WordPress, you can do something like <code>/feed/atom/?cat=-1234</code> to exclude posts which have a category with the ID of 1234.</p>

<p>There are some filters on the Rogue Scholar site which you might also be able to use.</p>

<h3 id="deleting-content"><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#deleting-content">Deleting Content</a></h3>

<p>I don't think there's a way to delete or retract content from Rogue Scholar's DOI system yet. If you accidentally publish something you didn't mean to, it'll live on in the archives forever.</p>

<h3 id="affiliations"><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#affiliations">Affiliations</a></h3>

<p>My ORCiD lists where I worked on certain dates. Initially, Rogue Scholar linked those to blog posts I wrote during my employment. However, all my posts were written in a personal capacity. It is possible to get those affiliations removed if they are inaccurate.</p>

<h3 id="more-vanity"><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#more-vanity">More Vanity</a></h3>

<p>I initially tried generating DOIs like <code>edent-00f47</code> - although it's a valid Base 32 string with a checksum, it carries semantic meaning (my name) so shouldn't really be used. Ah well! Back to random strings.</p>

<h3 id="humility"><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#humility">Humility</a></h3>

<p>Is this a valid use of the DOI ecosystem? A surprising number of my posts <a href="https://shkspr.mobi/blog/citations">have been referenced in academic papers</a> - but surely not <em>all</em> of my posts are worthy of getting a DOI? The problem is, I don't know when <a href="https://shkspr.mobi/blog/2018/06/how-i-became-leonardo-da-vinci-on-the-blockchain/">a shitpost</a> will hit the zeitgeist and become quoted in papers, books, and articles.</p>

<p>It feels a bit self-indulgent and a little pretentious to mint a new DOI for every previous and future post on this site. But it isn't like the DOI system is running out of space, is it?</p>

<h2 id="is-it-worth-it"><a href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#is-it-worth-it">Is it worth it?</a></h2>

<p>For me? Yes.</p>

<p>I think it is important that <a href="https://doi.org/10.64000/552ec-b8g03">scholarly blogs are properly referenced</a>. True, not <em>all</em> of my posts are cutting-edge research - but I'm always surprised which ones end up in someone's thesis or become part of a set-text.</p>

<p>I'm excited to see if this leads to an increase <em>or</em> decrease in my blog's visibility in academia.</p>

<p>If you have strong feelings either way about DOIs and/or blogs, please drop a comment in the box.</p>

<p>You may cite this post using <a href="https://doi.org/10.59350/5ck9b-kjv69">https://doi.org/10.59350/5ck9b-kjv69</a> 😃</p>
<img src="https://shkspr.mobi/blog/wp-content/themes/edent-wordpress-theme/info/okgo.php?ID=74717&amp;HTTP_REFERER=Atom" alt width="1" height="1" loading="eager">]]></content>
		
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			<link rel="replies" type="application/atom+xml" href="https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/feed/atom/" thr:count="8" />
			<thr:total>8</thr:total>
			</entry>
		<entry>
		<author>
			<name>Terence Eden</name>
							<uri>https://edent.tel/</uri>
						</author>

		<title type="html"><![CDATA[[RSS Club] Sorry for breaking your feed readers!]]></title>
		<link rel="alternate" type="text/html" href="https://shkspr.mobi/blog/2026/09/rss-club-sorry-for-breaking-your-feed-readers/" />

		<id>https://shkspr.mobi/blog/?p=75570</id>
		<updated>2026-09-15T07:37:02Z</updated>
		<published>2026-09-15T11:34:26Z</published>
		<category scheme="https://shkspr.mobi/blog" term="RSS Club" />
		<summary type="html"><![CDATA[You&#039;re part of the Groovy Gang because you&#039;re a member of RSS Club! These posts are only available on my RSS and Atom feed. This post is not available in the shops, on the web, via FTP, or anywhere else.  So, yeah, sorry! My last post apparently broke some people&#039;s RSS readers.  I had a code sample which said ＜marquee＞ - despite being properly escaped, some feed readers double-decoded it and tur…]]></summary>

					<content type="html" xml:base="https://shkspr.mobi/blog/2026/09/rss-club-sorry-for-breaking-your-feed-readers/"><![CDATA[<p><mark>You're part of the Groovy Gang because you're a member of <a href="https://daverupert.com/rss-club/">RSS Club</a>! These posts are only available on my RSS and Atom feed. This post is <strong>not</strong> available in the shops, on the web, via FTP, or anywhere else.</mark></p>

<p>So, yeah, sorry! My last post apparently broke some people's RSS readers.  I had a code sample which said <code>＜marquee＞</code> - despite being properly escaped, some feed readers double-decoded it and turned it into a literal marquee element!</p>

<p><video width="270" height="585" muted="" autoplay="" loop="" style="display:inline" src="https://shkspr.mobi/blog/wp-content/uploads/2026/09/feedscroll2.webm"></video><video width="270" height="600" muted="" autoplay="" loop="" style="display:inline" src="https://shkspr.mobi/blog/wp-content/uploads/2026/09/feedscroll.webm">&lt;/video?</video></p>

<p>With thanks to Neil and CaféHaine for the videos.</p>

<p>I got several reports that people's readers started scrolling like that and they'd <a href="https://github.com/nextcloud/news-android/issues/1719">raised issues with their feed reader</a>. Ooops! Sorry!</p>

<p>That said, as far as I can tell, the feed <em>is</em> escaped correctly and shouldn't cause problems.</p>

<p>Here's the code (I've added in some spaces to ensure it doesn't cause any issues):</p>

<pre><code class="language-xml">&lt;content type="html"&gt;
   &lt;![CDATA[&lt; p&gt; Lorem ipsum &lt;code&gt;&amp; lt;marquee&amp;gt;&lt;/code&gt; dolor sed.&lt;/p&gt;
</code></pre>

<p>So what's going on? The feed is generated by the latest version of WordPress which <a href="https://github.com/WordPress/wordpress-develop/blob/99e2de78a828d4fe472e37cf25fb0b2173e65c86/src/wp-includes/feed-atom.php#L89">uses <code>CDATA</code> to wrap HTML</a> in a feed.</p>

<p>There is a <a href="https://core.trac.wordpress.org/ticket/9992">17 year old discussion about whether this is conformant</a> on the WordPress issue tracker with the conclusion that it isn't incorrect and seems to work fine.</p>

<p>Is it OK? Is my feed broken or are a bunch of readers non-compliant?  Let's go back to basics. The Atom spec says</p>

<blockquote><p>If the value of "type" is "html", the content of atom:content MUST NOT contain child elements and SHOULD be suitable for handling as <a href="https://www.rfc-editor.org/info/rfc4287/#ref-HTML">HTML</a>.  The HTML markup MUST be escaped; for example, "<code>&lt;br&gt;</code>" as "<code>&amp;lt;br&gt;</code>".</p>

<p><a href="https://www.rfc-editor.org/info/rfc4287/#section-4.1.3.3">RFC 4287: The Atom Syndication Format</a></p></blockquote>

<p>Hmmmm. That would indicate that ampersand-l-t-semicolon should be interpreted as a less-than sign.</p>

<p>However, the whole thing is wrapped in <code>&lt;![CDATA[</code> which according to the XML spec means:</p>

<blockquote><p>CDATA sections may occur anywhere character data may occur; they are used to escape blocks of text containing characters which would otherwise be recognized as markup.</p>

<p><a href="https://www.w3.org/TR/REC-xml/#sec-cdata-sect">Extensible Markup Language (XML) 1.0 (Fifth Edition)</a></p></blockquote>

<p>So I <em>think</em> that a sensible feed-reader should see the CDATA block, grab the HTML inside it, and display it as-is. No need to unescape anything.</p>

<p>That said, I'll see if I can change my feed to <em>not</em> need this hybrid format. There's <a href="https://waspdev.com/articles/2026-05-11/avoid-using-cdata-in-rss">a brilliant blog post by Suren Enfiajyan</a> which makes the case that regular escaping is <em>probably</em> good enough.</p>

<p>If you've experienced this bug - or think that I'm generating my feeds in the wrong way - <a href="https://edent.tel">please get in touch</a>.</p>
<img src="https://shkspr.mobi/blog/wp-content/themes/edent-wordpress-theme/info/okgo.php?ID=75570&amp;HTTP_REFERER=Atom" alt width="1" height="1" loading="eager">]]></content>
		
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			<thr:total>0</thr:total>
			</entry>
		<entry>
		<author>
			<name>Terence Eden</name>
							<uri>https://edent.tel/</uri>
						</author>

		<title type="html"><![CDATA[Esoteric HTML - ismap vs CSS]]></title>
		<link rel="alternate" type="text/html" href="https://shkspr.mobi/blog/2026/09/esoteric-html-ismap-vs-css/" />

		<id>https://shkspr.mobi/blog/?p=73143</id>
		<updated>2026-09-14T11:35:05Z</updated>
		<published>2026-09-14T11:34:53Z</published>
		<category scheme="https://shkspr.mobi/blog" term="css" /><category scheme="https://shkspr.mobi/blog" term="HTML5" /><category scheme="https://shkspr.mobi/blog" term="webdev" />
		<summary type="html"><![CDATA[The HTML specification is old and, while there is beauty in longevity, there&#039;s an inevitable build-up of boondoggles and baggage. Some elements like &#60;marquee&#62; have sadly been consigned to the dustbin of history - but there are still vestigial attributes just waiting to trip up the unwary.  If you&#039;re young, you may never have heard of Image Maps. Back in the bad-old-days, there weren&#039;t many good…]]></summary>

					<content type="html" xml:base="https://shkspr.mobi/blog/2026/09/esoteric-html-ismap-vs-css/"><![CDATA[<p>The HTML specification is old and, while there is beauty in longevity, there's an inevitable build-up of boondoggles and baggage. Some elements like <code>&lt;marquee&gt;</code> have sadly been consigned to the dustbin of history - but there are still vestigial attributes just waiting to trip up the unwary.</p>

<p>If you're young, you may never have heard of Image Maps. Back in the bad-old-days, there weren't many good options for laying out a pixel-perfect HTML page. One option was to draw your website in an image editor, load it into a website <em>as an image</em>, and then make certain areas of the image clickable.</p>

<p>One way to do this was to add the attribute <code>ismap</code>. It is <em>only</em> valid on <code>&lt;img&gt;</code> elements which are inside an <code>&lt;a href=…&gt;</code> element. Like so:</p>

<pre><code class="language-html">&lt;a href="click.php"&gt;
    &lt;img ismap src="img.png" width="100" height="100"&gt;
&lt;/a&gt;
</code></pre>

<p>When you click on that image, you don't go to <code>click.php</code> - instead you go to <code>click.php?12,34</code> where the two numbers represent the X and Y coordinates of <em>where</em> on the image you clicked. That's brilliant! Your server knows the size of the image - so if you click on the top half it can take you to one place, and if you click in the lower left corner you can go to another.</p>

<p>Brilliant!</p>

<p>Except, of course, there's a catch!</p>

<p>The <a href="https://html.spec.whatwg.org/multipage/embedded-content.html#dom-img-ismap">specification of the <code>&lt;img&gt;</code> element</a> is a little obtuse. Merely saying:</p>

<blockquote><p>The ismap attribute […] indicates by its presence that the element provides access to a server-side image map. This affects how events are handled on the corresponding a element.</p></blockquote>

<p>Instead, the details are in <a href="https://html.spec.whatwg.org/multipage/links.html#links-created-by-a-and-area-elements">4.6.2 Links created by a and area elements</a>:</p>

<blockquote><p>set x to the distance in CSS pixels from the left edge of the image to the location of the click, and set y to the distance in CSS pixels from the top edge of the image to the location of the click.</p></blockquote>

<p>Did you notice the gotcha?</p>

<blockquote><p><strong>the distance in CSS pixels</strong></p></blockquote>

<p>This is <em>not</em> based on the actual size of the image! It is based on the layout</p>

<p>Let's suppose you have an image which is 100 x 100 pixels. It is added to the website like this:</p>

<p><code>&lt;img src="100.png" width="100" height="100" ismap&gt;</code></p>

<p>Click on this image and you'll see that your X and Y positions are based on the natural size of the image.</p>

<p><a href="."><img src="https://placekittens.com/100/100" width="100" height="100" ismap="" alt="A cute kitten"></a></p>

<p>But suppose you change the HTML to this:</p>

<p><code>&lt;img src="100.png" width="500" height="20" ismap&gt;</code></p>

<p>When you click on the image, the X &amp; Y positions are <em>not</em> based on the actual size of the image; they're based on its layout size.</p>

<p><a href="."><img src="https://placekittens.com/100/100" width="500" height="20" ismap="" style="height:20px" alt="A distorted image of a kitten"></a></p>

<p>Suppose you use CSS to resize the image:</p>

<p><code>&lt;img src="100.png" width="100" height="100" ismap style="width:7em;height:30ch"&gt;</code></p>

<p><a href="."><img src="https://placekittens.com/100/100" width="100" height="100" ismap="" style="width:7em;height:30ch" alt="A distorted image of a kitten"></a></p>

<p>The X and Y aren't based on the image's natural size, nor their declared height and width. Instead they're based on the size on screen determined by CSS.</p>

<p>And, of course, that's not necessarily <em>your</em> CSS! If the user has turned off style sheets, supplied their own, or uses an accessibility tool - the CSS size of the image might be <em>vastly</em> different from what you intended.</p>

<p>If you have an image 100 pixels wide and you want people clicking on the left half to go to a different location to the people clicking on the right half, you might have server-side code which says:</p>

<pre><code class="language-_">if X &lt; 50 :
    return page1.html
else
    return page2.html
</code></pre>

<p>But if the CSS has stretched, shrunk, skewed, or distorted the image then you have <em>no way of knowing</em> where the user clicked.</p>

<p>As far as I can tell, this behaviour is the same in all major browsers.</p>

<p>Basically, what I'm saying is, don't use <code>ismap</code> unless you're absolutely sure that there will be no CSS shenanigans. Even then, it probably isn't worth the risk.</p>
<img src="https://shkspr.mobi/blog/wp-content/themes/edent-wordpress-theme/info/okgo.php?ID=73143&amp;HTTP_REFERER=Atom" alt width="1" height="1" loading="eager">]]></content>
		
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			<thr:total>12</thr:total>
			</entry>
		<entry>
		<author>
			<name>Terence Eden</name>
							<uri>https://edent.tel/</uri>
						</author>

		<title type="html"><![CDATA[The expectations of privacy in driverless cars]]></title>
		<link rel="alternate" type="text/html" href="https://shkspr.mobi/blog/2026/09/the-expectations-of-privacy-in-driverless-cars/" />

		<id>https://shkspr.mobi/blog/?p=73168</id>
		<updated>2026-09-13T11:33:41Z</updated>
		<published>2026-09-13T11:34:13Z</published>
		<category scheme="https://shkspr.mobi/blog" term="AI" /><category scheme="https://shkspr.mobi/blog" term="automation" /><category scheme="https://shkspr.mobi/blog" term="car" /><category scheme="https://shkspr.mobi/blog" term="privacy" /><category scheme="https://shkspr.mobi/blog" term="robots" />
		<summary type="html"><![CDATA[Do riders in autonomous vehicles think that they are in a private space? Here&#039;s a fascinating story from California where an robotaxi was redirected from its intended destination and, instead, delivered its misbehaving passengers to the police.  The 15-year-old passengers were riding in a driverless autonomous car around San Mateo Monday afternoon. The teens drank alcohol inside the Waymo taxi…]]></summary>

					<content type="html" xml:base="https://shkspr.mobi/blog/2026/09/the-expectations-of-privacy-in-driverless-cars/"><![CDATA[<p>Do riders in autonomous vehicles think that they are in a private space? Here's a fascinating story from California where an robotaxi was redirected from its intended destination and, instead, delivered its misbehaving passengers to the police.</p>

<blockquote><p>The 15-year-old passengers were riding in a driverless autonomous car around San Mateo Monday afternoon. The teens drank alcohol inside the Waymo taxi and shot Orbeez beads with a toy gun toward other vehicles.</p>

<p>A Waymo employee, who was remotely monitoring the car, tricked the unruly teenagers, authorities said. The employee told the young passengers that the Waymo was having mechanical issues and needed to stop.</p>

<p>Unknown to the teens, the employee had also called the San Mateo Police Department to report that a gun was firing from the car.</p>

<p><a href="https://www.kron4.com/news/bay-area/heres-how-waymo-tricked-unruly-teen-passengers-in-san-mateo/">Here’s how Waymo tricked unruly teen passengers in San Mateo</a></p></blockquote>

<p>Is that OK?</p>

<p>Kids shooting (albeit fake) guns out of cars is bad. I've no problem with the long arm of the law feeling their collars.</p>

<p>But what sort of reasonable expectation of privacy do you have when you jump into a driverless car?</p>

<p>If you have a blazing row with your partner while sat in the back of a black cab, the driver's going to hear, right? There's no privacy expectation although you might rely on their discretion.</p>

<p>Take a phone call and arrange a drug deal, the driver might turn you in to the police. They're not a confidant, are they?</p>

<p>Kiss someone you shouldn't and you accept the risk that the driver might both notice and care.</p>

<p>But when there's no driver, there's no risk of your privacy being invaded is there?</p>

<blockquote><p>Nine former Tesla employees told Reuters that Tesla workers shared customer videos and images recorded by in-car cameras between 2019 and 2022.</p>

<p><a href="https://observer.com/2023/04/tesla-camera-recording-privacy-concern/">Tesla Workers Shared ‘Intimate’ Videos Recorded By In-Car Cameras</a></p></blockquote>

<p>Ah.</p>

<p>I don't know how Waymo was alerted to the problems in the car. Perhaps someone called them and reported the numberplate. Perhaps the car heard raised voices and sent an alert. Perhaps Waymo just regularly drops in on all its customers.</p>

<p>Rummaging through Waymo's various privacy policies eventually leads to this <a href="https://support.google.com/waymo/answer/9190819">rather ambiguous page</a> which describes how they monitor the inside of their vehicles.</p>

<blockquote><p>Our autonomous vehicles are equipped with an advanced suite of sensors – including cameras and microphones – that act as the 'eyes and ears' of our Waymo Driver.</p>

<strong>Cameras inside the car</strong>

<p>Cameras are a way for us to make sure that your trip goes smoothly. Among other things, we may use cameras to:</p>

<ul>
  <li>Make sure that cars are clean</li>
  <li>Find lost items</li>
  <li>Provide help in case of emergency</li>
  <li><i>Check that in-car rules are being followed</i> <small>[Emphasis added]</small></li>
  <li>Improve products and services</li>
  <li><i>Promote safety and security</i> <small>[Emphasis added]</small></li>
</ul>

<p>Our Support team may review video under certain circumstances, including after an issue is brought to our attention. Occasionally, in more urgent circumstances, Support may access live video during a trip.</p>

<strong>Microphones inside the car</strong>

<p>The microphones inside the car are only on during voice calls with Rider Support or when you actively choose to enable microphones inside the car.</p></blockquote>

<p>To me, that sounds like riders' voices aren't automatically sent back to the mothership. Indeed, they're at pains to say:</p>

<blockquote><p>Waymo vehicles also have a number of sensors, including our audio-detection system used to detect police and emergency vehicle sirens. Waymo has implemented technical and procedural safeguards designed to limit the collection of any human voice data from these microphones.</p></blockquote>

<p>So there is <em>some</em> acknowledgement of privacy - for our voices at least. Meanwhile, passengers are <a href="https://www.brautiganarchives.xyz/machines.html">all watched over by machines of loving grace</a> or, at the very least, fallible humans with prurient interests.</p>

<p>About a decade ago, people were theorising that a driverless cars would one day deliver to you <a href="https://www.reddit.com/r/Showerthoughts/comments/5qg125/eventually_a_selfdriving_car_will_deliver_a_dead/">a rider who died on the journey</a>. I don't think that's happened yet - instead, we have cars watching what what we do. Silently judging us picking our noses. Examining our body language for signs of stress. Tracking our breathing patterns and heart-rates to ensure we aren't going to cause damage to the vehicle.</p>

<p>Not listening though. That would be a step too far.</p>

<p>Besides, who needs to use a microphone when you've got a high-resolution camera backed by AI?</p>

<p></p><div style="width: 620px;" class="wp-video"><video class="wp-video-shortcode" id="video-73168-2" width="620" height="349" preload="metadata" controls="controls"><source type="video/mp4" src="https://shkspr.mobi/blog/wp-content/uploads/2026/09/2001-lip-reading-web.mp4?_=2"><a href="https://shkspr.mobi/blog/wp-content/uploads/2026/09/2001-lip-reading-web.mp4">https://shkspr.mobi/blog/wp-content/uploads/2026/09/2001-lip-reading-web.mp4</a></video></div><p></p>

<p>Just as I finished writing this post, a story broke about how a <a href="https://www.latimes.com/california/story/2026-09-12/juveniles-riding-in-waymo-arrested-after-police-find-ghost-gun">Waymo pulled over and called the police on riders who had "ghost gun"</a>. The company said it alerted the authorities after detecting a terms of service violation.</p>

<p>Of course, it didn't say <em>how</em> it detected that!</p>

<p>I also find it curious that in both cases, the alleged perpetrators were juveniles. Maybe children have less of a right to privacy than adults?</p>

<p>I guess when you ride alone, you ride with a snitch.</p>
<img src="https://shkspr.mobi/blog/wp-content/themes/edent-wordpress-theme/info/okgo.php?ID=73168&amp;HTTP_REFERER=Atom" alt width="1" height="1" loading="eager">]]></content>
		
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			</entry>
		<entry>
		<author>
			<name>Terence Eden</name>
							<uri>https://edent.tel/</uri>
						</author>

		<title type="html"><![CDATA[ActivityPub - How to send an updated user profile to Mastodon and the Fediverse]]></title>
		<link rel="alternate" type="text/html" href="https://shkspr.mobi/blog/2026/09/activitypub-how-to-send-an-updated-user-profile-to-mastodon-and-the-fediverse/" />

		<id>https://shkspr.mobi/blog/?p=74470</id>
		<updated>2026-09-13T06:08:41Z</updated>
		<published>2026-09-12T11:34:02Z</published>
		<category scheme="https://shkspr.mobi/blog" term="ActivityBot" /><category scheme="https://shkspr.mobi/blog" term="ActivityPub" /><category scheme="https://shkspr.mobi/blog" term="fediverse" /><category scheme="https://shkspr.mobi/blog" term="mastodon" />
		<summary type="html"><![CDATA[Let&#039;s suppose you&#039;ve updated the description of your ActivityPub account from &#34;World&#039;s Number 1 Taylor Swift Fan&#34; to &#34;This account is now a Nickleback Truther&#34;. How do you let the rest of the Fediverse know that you&#039;ve changed your allegiance?  By default, most Mastodon instances won&#039;t periodically poll your account information just to see if you&#039;ve updated it. So how does the information get…]]></summary>

					<content type="html" xml:base="https://shkspr.mobi/blog/2026/09/activitypub-how-to-send-an-updated-user-profile-to-mastodon-and-the-fediverse/"><![CDATA[<p>Let's suppose you've updated the description of your ActivityPub account from "World's Number 1 Taylor Swift Fan" to "This account is now a Nickleback Truther". How do you let the rest of the Fediverse know that you've changed your allegiance?</p>

<p>By default, most Mastodon instances won't periodically poll your account information just to see if you've updated it. So how does the information get from your server to your followers' servers?</p>

<p>This wasn't immediately obvious to me, but I got a clue from reading <a href="https://shkspr.mobi/blog/2026/09/book-review-activitypub-by-evan-prodromou/">Evan Prodromou's book on ActivityPub</a>:</p>

<blockquote><p>The Update activity type is for updating the properties of an object represented by the object property.</p>

<p>The most common types of objects that can be updated are content objects, like Note or Image. Actor types (like Person) and Question activity types can also be updated.</p></blockquote>

<p>Aha!</p>

<p>You need to craft an <code>Update</code> message which has as its object the <em>new</em> user information. That needs to be sent to the inbox of all your followers.</p>

<p>Something like this:</p>

<pre><code class="language-json">{
    "@context": "https://www.w3.org/ns/activitystreams",
    "actor": "https://example.com/user",
    "id": "6a9162a6-a8e5-ca0f-9c08-8e6b814acef8",
    "published": "2026-08-31T12:34:56+01:00",
    "to": "https://www.w3.org/ns/activitystreams#Public",
    "type": "Update",
    "object": {
        "@context": [
            "https://www.w3.org/ns/activitystreams",
            "https://w3id.org/security/v1"
        ],
        "id": "https://example.com/user",
        "name": "My new name",
        "summary": "A brand new description!",
        …
    },
}
</code></pre>

<p>Obviously the <em>full</em> user information is a bit more than that - it will include inbox details, public keys, avatars, etc. The <code>published</code> property in the Update activity should be when you changed your details - not when the account was created.</p>

<p>Once that was sent, Mastodon immediately reflected the changes.</p>

<h2 id="thanks-to-nlnet"><a href="https://shkspr.mobi/blog/2026/09/activitypub-how-to-send-an-updated-user-profile-to-mastodon-and-the-fediverse/#thanks-to-nlnet">Thanks to NLnet</a></h2>

<p>This blog post was funded in part by the work I'm doing for my NLnet NGI0 grant to develop <a href="https://gitlab.com/edent/activity-bot">ActivityBot</a>.</p>

<p><a href="https://nlnet.nl/project/ActivityBot/"><img src="https://shkspr.mobi/blog/wp-content/uploads/2026/08/NGI-logos.webp" alt="NLnet logo." width="900" height="200" class="aligncenter"></a></p>
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			</entry>
		<entry>
		<author>
			<name>Terence Eden</name>
							<uri>https://edent.tel/</uri>
						</author>

		<title type="html"><![CDATA[[RSS Club] Sneak peek at new DOI functionality]]></title>
		<link rel="alternate" type="text/html" href="https://shkspr.mobi/blog/2026/09/rss-club-sneak-peek-at-new-doi-functionality/" />

		<id>https://shkspr.mobi/blog/?p=74757</id>
		<updated>2026-09-11T09:48:42Z</updated>
		<published>2026-09-11T11:34:12Z</published>
		<category scheme="https://shkspr.mobi/blog" term="RSS Club" />
		<summary type="html"><![CDATA[If you&#039;re reading this, you&#039;re part of RSS Club! A top secret society of cool people who subscribe to my feed. This post is not available on the web or via email.  I&#039;ve been playing about with Rogue Scholar. It&#039;s an open-access publication which allows blogs to get a persistent Digital Object Identifier.  If I&#039;ve set everything up correctly (not a given) then all new posts on this site will be…]]></summary>

					<content type="html" xml:base="https://shkspr.mobi/blog/2026/09/rss-club-sneak-peek-at-new-doi-functionality/"><![CDATA[<p><mark>If you're reading this, you're part of <a href="https://daverupert.com/rss-club/">RSS Club</a>! A <em>top secret</em> society of cool people who subscribe to my feed. This post is <strong>not</strong> available on the web or via email.</mark></p>

<p>I've been playing about with <a href="https://rogue-scholar.org/">Rogue Scholar</a>. It's an open-access publication which allows blogs to get a persistent <a href="https://en.wikipedia.org/wiki/Digital_object_identifier">Digital Object Identifier</a>.</p>

<p>If I've set everything up correctly (not a given) then all new posts on this site will be issued with a DOI. Hopefully, this will not include RSS Club posts - as I'd like to keep them as a special private treat just between you and me.</p>

<p>I'm in the process of writing a WordPress plugin to retrieve the DOI and add it to posts. I'm not sure if there's a sensible way to add it into an RSS feed, but I'll give it a go.</p>

<p>Will this be useful? I don't know. My posts sometimes get <a href="https://shkspr.mobi/blog/citations">referenced in proper academic works</a> - I'm not sure if this'll make any difference to that. But it is nice to experiment with these things.</p>

<p>If you have any experience with DOI or Rogue Scholar - please <a href="https://edent.tel/">get in touch</a>.</p>

<p>Thanks for being a member of RSS Club - you rock 😃</p>
<img src="https://shkspr.mobi/blog/wp-content/themes/edent-wordpress-theme/info/okgo.php?ID=74757&amp;HTTP_REFERER=Atom" alt width="1" height="1" loading="eager">]]></content>
		
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			<thr:total>0</thr:total>
			</entry>
		<entry>
		<author>
			<name>Terence Eden</name>
							<uri>https://edent.tel/</uri>
						</author>

		<title type="html"><![CDATA[Put an AV test at the start of your slides]]></title>
		<link rel="alternate" type="text/html" href="https://shkspr.mobi/blog/2026/09/put-an-av-test-at-the-start-of-your-slides/" />

		<id>https://shkspr.mobi/blog/?p=68346</id>
		<updated>2026-09-02T09:08:33Z</updated>
		<published>2026-09-10T11:34:10Z</published>
		<category scheme="https://shkspr.mobi/blog" term="presentations" />
		<summary type="html"><![CDATA[For years, I&#039;ve had a test-card at the start of my slides. Before I start my talk, I can immediately see if the aspect ratio is wrong, colours are off, or any other visual issues with the presentation.    A few years ago I was invited to give a talk and was assured that the venue was set up for audio as well as video. I dutifully filled my slides with with demo videos containing sound. None of…]]></summary>

					<content type="html" xml:base="https://shkspr.mobi/blog/2026/09/put-an-av-test-at-the-start-of-your-slides/"><![CDATA[<p>For years, I've had a <a href="https://shkspr.mobi/blog/2017/11/put-a-test-card-at-the-start-of-your-slides/">test-card at the start of my slides</a>. Before I start my talk, I can immediately see if the aspect ratio is wrong, colours are off, or any other visual issues with the presentation.</p>

<img src="https://shkspr.mobi/blog/wp-content/uploads/2017/10/Test-Card-on-a-screen.jpg" alt="A test card is displaying on a television screen" width="1024" height="768" class="alignleft size-full wp-image-28772">

<p>A few years ago I was invited to give a talk and was assured that the venue was set up for audio as well as video. I dutifully filled my slides with with demo videos containing sound. None of them worked. Somewhere between the HDMI output of the presentation laptop and the speakers, the audio went <abbr title="Absent Without Leave">AWOL</abbr>.</p>

<p>Ever since then, I've placed an audio test slide at the start of my presentations. There's <a href="https://www.youtube.com/results?search_query=sound+sync+test">a good range of videos on YouTube</a> - pick one you like, embed it into your slides, and play it before your talk starts.</p>

<p>Over the years, I've found the following "bugs" with event AV setups:</p>

<ul>
<li>No sound.</li>
<li>Only left channel working.</li>
<li>Severe latency between audio and video.</li>
<li>Garbled sound.</li>
<li>Sound routing to the room but not the livestream.</li>
<li>Feedback / howl around when sound playing.</li>
</ul>

<p>Whether events are professionally run or community managed, you can never guarantee that sound will work. Add subtitles to your videos. If possible, add a sign-language interpreter. And, if all else fails, hold your microphone to your laptop's speakers.</p>
<img src="https://shkspr.mobi/blog/wp-content/themes/edent-wordpress-theme/info/okgo.php?ID=68346&amp;HTTP_REFERER=Atom" alt width="1" height="1" loading="eager">]]></content>
		
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			<thr:total>6</thr:total>
			</entry>
		<entry>
		<author>
			<name>Terence Eden</name>
							<uri>https://edent.tel/</uri>
						</author>

		<title type="html"><![CDATA[ActivityPub - Is it worth defending against replay attacks and message/signature time skew?]]></title>
		<link rel="alternate" type="text/html" href="https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/" />

		<id>https://shkspr.mobi/blog/?p=74622</id>
		<updated>2026-09-08T09:42:04Z</updated>
		<published>2026-09-08T11:34:51Z</published>
		<category scheme="https://shkspr.mobi/blog" term="ActivityBot" /><category scheme="https://shkspr.mobi/blog" term="ActivityPub" /><category scheme="https://shkspr.mobi/blog" term="http" /><category scheme="https://shkspr.mobi/blog" term="security" />
		<summary type="html"><![CDATA[Here&#039;s a problem that I&#039;ve found with ActivityBot - my little ActivityPub server. Sometimes it receives messages which were originally sent months ago. Why does that happen and is it risky to accept and process them?  My tl;dr is that it probably isn&#039;t worth worrying about. But I&#039;d love someone to tell me why I&#039;m wrong.  Here&#039;s my thinking:  Table of ContentsCausesIs that a problem?What are we…]]></summary>

					<content type="html" xml:base="https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/"><![CDATA[<p>Here's a problem that I've found with <a href="https://gitlab.com/edent/activity-bot/">ActivityBot</a> - my little ActivityPub server. Sometimes it receives messages which were originally sent <em>months</em> ago. Why does that happen and is it risky to accept and process them?</p>

<p>My tl;dr is that it <em>probably</em> isn't worth worrying about. But I'd love someone to tell me why I'm wrong.</p>

<p>Here's my thinking:</p>

<p></p><nav role="doc-toc"><menu><li><h2 id="table-of-contents"><a href="https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#table-of-contents">Table of Contents</a></h2><menu><li><a href="https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#causes">Causes</a></li><li><a href="https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#is-that-a-problem">Is that a problem?</a></li><li><a href="https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#what-are-we-trying-to-protect-against">What are we trying to protect against?</a></li><li><a href="https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#putting-it-all-together">Putting it all together</a></li><li><a href="https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#no-youre-wrong-and-i-can-prove-it">No! You're wrong and I can prove it!</a></li></menu></li></menu></nav><p></p>

<h2 id="causes"><a href="https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#causes">Causes</a></h2>

<p>All ActivityPub messages should have a "published" timestamp in their body. Some will have an "updated" timestamp. That tells you, unsurprisingly, when the message is alleged to have been originally published or updated. That time might be very different to the time you receive the message.</p>

<p>There are, I think, three different reasons why a server might receive a message which has an out-of-date timestamp.</p>

<p>The first is that sometimes servers are just slow. Processing thousands of messages at the same time means that some of those messages take a while to send.  <a href="https://shkspr.mobi/blog/2023/09/how-far-did-my-post-go-on-the-fediverse/">ActivityPub is one big chain-mail</a> so it can take several minutes for a message to be sent to all your followers.</p>

<p>Similarly, your server might be slow. If it doesn't acknowledge receipt of a message, the original server will try sending it again. Sometimes that can take a while.</p>

<p>Finally, some servers take a relaxed view of standards. They send an update to an old message but keep the original publication date. Ideally, they'd use an "updated" timestamp but quite often they don't.</p>

<p>For the purposes of checking the legitimacy of the message, <strong>you do not need to check when a message says it was published or updated</strong>. You might want to check it isn't an <em>obviously</em> bogus date like far in the future or impossibly far in the past - but that's up to you.</p>

<p>It is normal that your server receives messages which appear to have been published at a totally different time from now.</p>

<h2 id="is-that-a-problem"><a href="https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#is-that-a-problem">Is that a problem?</a></h2>

<p><em>Probably</em> not.</p>

<p>As described above, there are various reasons why a message may be delayed in transit - or may appear to come from the distant past.</p>

<p>What we <em>can</em> check is when the message was cryptographically signed by the sending server. This is independent of its published or updated timestamp.</p>

<p>HTTP requests to your server will have a <code>date</code> header which looks like <code>Tue, 01 Sep 2026 15:54:21 GMT</code> - this is in the slightly peculiar and Anglocentric <a href="https://www.rfc-editor.org/info/rfc5322/#section-3.3">RFC 5322 format</a>.</p>

<p>New style RFC 9421 headers will also have a <code>signature-input</code> header which will contain something like <code>created=1788278061</code>. That uses the slightly obscure <a href="https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap04.html#tag_04_16">UNIX / POSIX time</a> which counts seconds since the "Epoch" of 1st January 1970.</p>

<p>If you <a href="https://www.epochconverter.com/">convert the UNIX time</a> to something more modern, you should get an <em>identical</em> value to the <code>date</code> header.</p>

<p>But that isn't always the case. For example, <a href="https://www.rfc-editor.org/rfc/rfc9421.html#:~:text=Tue%2C%2020%20Apr%202021%2002%3A07%3A55%20GMT,-Content%2DType">the RFC 9421 standard gives this example</a>:</p>

<pre><code class="language-_">Date: Tue, 20 Apr 2021 02:07:55 GMT
"@signature-params": ("@method" "@authority" "@path" \
  "content-digest" "content-length" "content-type")\
  ;created=1618884473;keyid="test-key-rsa-pss"
</code></pre>

<p>Converting <code>1618884473</code> to normal time gives Tue, 20 Apr 2021 02:07:<strong>53</strong> - a two second difference.</p>

<p>If the <code>date</code> and <code>created</code> values differ significantly - that may indicate that the message is untrustworthy. Or that there was a delay between the signing and the sending.</p>

<p>The spec says:</p>

<blockquote><p>The Date header field value represents the timestamp of the HTTP message. However, the creation time of the signature itself is encoded in the created signature parameter. These two values can be different, depending on how the signature and the HTTP message are created and serialized. Applications processing signatures for valid time windows should use the created signature parameter for such calculations. An application could also put limits on how much skew there is between the Date field and the created signature parameter, in order to limit the application of a generated signature to different HTTP messages.</p>

<p><a href="https://www.rfc-editor.org/rfc/rfc9421.html#section-7.2.4">7.2.4. Choosing Signature Parameters and Derived Components over HTTP Fields</a></p></blockquote>

<p>But, of course, it doesn't tell you how much skew is problematic. It's up to you how much skew you're prepared to accept.</p>

<p>So that's the difference between the sent time and the signed time. The next time to check is your own. As we've discussed, sometimes servers are slow sending things out. Would you accept a request that was signed five minutes ago? Five days ago? Five months ago? What amount of difference is dangerous?</p>

<p>Here's what various services and sages have to say:</p>

<h3 id="mastodon"><a href="https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#mastodon">Mastodon</a></h3>

<blockquote><p>The request contains a Date header. Compare it with current date and time within a reasonable time window to prevent replay attacks.</p>

<p><a href="https://blog.joinmastodon.org/2018/07/how-to-make-friends-and-verify-requests/">How to make friends and verify requests</a></p></blockquote>

<p>What is "reasonable"? The <a href="https://github.com/mastodon/mastodon/blob/89bc0eb42609463d4b11e1604dacc37332a0f5ab/app/lib/signed_request.rb#L5">source code</a> suggests one hour.</p>

<h3 id="grishka"><a href="https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#grishka">Grishka</a></h3>

<blockquote><p>Time in the Date header must differ from the recipient server’s clock by no more than 30 seconds</p>

<p><a href="https://grishka.me/blog/activitypub-from-scratch/">A bare-minimum ActivityPub server from scratch</a></p></blockquote>

<h3 id="evan-prodromou"><a href="https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#evan-prodromou">Evan Prodromou</a></h3>

<blockquote><p><code>static #maxDateDiff = 5 * 60 * 1000 // 5 minutes</code></p>

<p><a href="https://github.com/evanp/activitypub-bot/blob/main/lib%2Fhttpsignatureauthenticator.js#L8">activitypub-bot</a></p></blockquote>

<h3 id="swicg"><a href="https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#swicg">SWICG</a></h3>

<blockquote><p>The standards don't give a concrete time window to use for this comparison. In practice, an hour plus a few minutes buffer in either direction may be a good value, to account for both clock skew and differences in time zone/daylight savings time configuration across systems.</p>

<p><a href="https://swicg.github.io/activitypub-http-signature/#how-to-verify-a-signature">How To Verify a Signature</a></p></blockquote>

<h3 id="others"><a href="https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#others">Others</a></h3>

<p>Without naming names, it looks like a bunch of popular servers don't check whether there's a significant difference between the date the request was signed and the date it was received.</p>

<h3 id="summary"><a href="https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#summary">Summary</a></h3>

<p>Various documents and implementations recommend anything between 30 seconds to "a bit more than 60 minutes". Or they just ignore any date difference.</p>

<p>What's the right answer? What happens if the signed date is significantly different from the current date?</p>

<h2 id="what-are-we-trying-to-protect-against"><a href="https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#what-are-we-trying-to-protect-against">What are we trying to protect against?</a></h2>

<p>Replay Attacks. Suppose someone is listening to the communications between the sending server and your server. They copy the message that is sent to you. Later they send it again!</p>

<p>At this point, you might be thinking "so what?" and… I'm inclined to agree with you!</p>

<p>What's the worst that could happen if you received the same message multiple times? Two things that I can think of.</p>

<p>Firstly, it might <em>not</em> be the same message. It is possible to send a new message but with old headers. An attacker could make someone post "I hate Taylor Swift" against their will and watch as legions of fans disembowel the victim.</p>

<p>Except, I don't think this is likely. The signature in the header contains a hash of the message being sent. If you are properly validating the signature, a changed message will have a different hash from the one in the original message. You don't need to check timestamps, you just need to check if the hashes match.</p>

<p>Secondly, <a href="https://www.freecodecamp.org/news/idempotence-explained">idempotence</a>. That's a fancy word for "pressing the button multiple times should only result in one action".</p>

<p>What happens if a user appears to send you multiple "like" messages for a single post? You only record one like.</p>

<p>What if they send multiple messages with the same content? Well, each will have a unique ID in the message - so you only post it once.</p>

<p>What if they send multiple <em>anythings</em>? I can't think of any ActivityPub action which would not be idempotent.</p>

<p>About the worst thing I can think of is this:</p>

<ul>
<li>Alice sends a message to you saying "I want to follow Bob".</li>
<li>Mallory intercepts this message.</li>
<li>You record Alice is now following Bob.</li>
<li>Alice sends a message to you saying "I want to <em>unfollow</em> Bob".</li>
<li>You record the severed relationship.</li>
<li>Mallory replays the original follow message.</li>
<li>You record Alice is now following Bob.</li>
</ul>

<p>It's also possible the following could happen:</p>

<ul>
<li>Alice posts a message saying "I love The Beatles".</li>
<li>You record Alice's message and display it on the timeline.</li>
<li>Alice updates her post to say "I love the Rolling Stones".</li>
<li>Mallory intercepts this message.</li>
<li>You record Alice's updated message and display the new version on the timeline.</li>
<li>Alice updates her post yet again to say "I love the Spice Girls".</li>
<li>You record Alice's updated message and display the new version on the timeline.</li>
<li>Mallory replays the original update message.</li>
<li>You now display that Alice loves the Stones rather than Spice Girls.</li>
</ul>

<p>Perhaps the same can happen with like/unlike, block/unblock, boost/unboost.</p>

<p>But none of that is significantly prevented by checking the date.</p>

<p>Ultimately, it is up to your sever to check the unique ID of each message and refuse to action any repeated messages. You may not want to trust the unique ID which is sent with the message. If that's the case, you can calculate your own - perhaps using a hash of the contents, the signature, or some other process which will generate an ID based on the message.</p>

<h2 id="putting-it-all-together"><a href="https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#putting-it-all-together">Putting it all together</a></h2>

<p>Here's what you need to do to prevent replay attacks:</p>

<ol>
<li>Independently calculate the hash of the message received.</li>
<li>Validate that your calculated hash matches the hash sent in the message's HTTP headers.

<ul>
<li>If not, this is a potential replay attack and the message must be ignored.</li>
</ul></li>
<li>Verify that the signature received in the message's HTTP headers includes the message hash and is cryptographically valid.

<ul>
<li>If not, the signature is invalid  and the message must be ignored.</li>
</ul></li>
<li>Has the received message's unique ID already been processed?

<ul>
<li>If so, refuse to process it again.</li>
</ul></li>
</ol>

<p>I don't see what checking the timestamp of the HTTP signature has to do with anything. Someone who has access to the original messages and their headers could send them milliseconds after the original delivery.</p>

<p>I think it is probably <em>pragmatic</em> to give messages 60ish minutes grace before dropping them. Delays happen, but anything more significant than an hour <em>might</em> indicate a attack. But, equally, might just mean that the Internet is having a slow day.</p>

<p>If you are correctly checking signatures and hashes, I don't think you need to worry about skew between signature date and delivery date.</p>

<h2 id="no-youre-wrong-and-i-can-prove-it"><a href="https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#no-youre-wrong-and-i-can-prove-it">No! You're wrong and I can prove it!</a></h2>

<p>Please tell me where I have erred! Stick a comment in the box or drop me an email. If I've made a massive or subtle mistake, I'd love to know what.</p>
<img src="https://shkspr.mobi/blog/wp-content/themes/edent-wordpress-theme/info/okgo.php?ID=74622&amp;HTTP_REFERER=Atom" alt width="1" height="1" loading="eager">]]></content>
		
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			</entry>
		<entry>
		<author>
			<name>Terence Eden</name>
							<uri>https://edent.tel/</uri>
						</author>

		<title type="html"><![CDATA[The purpose of DNS is to spread scams]]></title>
		<link rel="alternate" type="text/html" href="https://shkspr.mobi/blog/2026/09/the-purpose-of-dns-is-to-spread-scams/" />

		<id>https://shkspr.mobi/blog/?p=74588</id>
		<updated>2026-09-05T17:12:13Z</updated>
		<published>2026-09-06T11:34:20Z</published>
		<category scheme="https://shkspr.mobi/blog" term="ICANN" /><category scheme="https://shkspr.mobi/blog" term="internet" /><category scheme="https://shkspr.mobi/blog" term="scam" /><category scheme="https://shkspr.mobi/blog" term="spam" /><category scheme="https://shkspr.mobi/blog" term="tld" /><category scheme="https://shkspr.mobi/blog" term="web" />
		<summary type="html"><![CDATA[I imagine everyone here has received an unsolicited message telling them that their tax is overdue and that they urgently need to visit Genuine-Tax-Payment-Website.fart or that a parcel is delayed at customs and you can pay a small sum for its release at Almost-The-Right-Acronym.ak  You know it is a scam. Most people just mark as spam and move on with their day. But a significant number of people …]]></summary>

					<content type="html" xml:base="https://shkspr.mobi/blog/2026/09/the-purpose-of-dns-is-to-spread-scams/"><![CDATA[<p>I imagine everyone here has received an unsolicited message telling them that their tax is overdue and that they urgently need to visit Genuine-Tax-Payment-Website.fart or that a parcel is delayed at customs and you can pay a small sum for its release at Almost-The-Right-Acronym.ak</p>

<p>You know it is a scam. Most people just mark as spam and move on with their day. But a significant number of people don't. They hastily visit the site, tap in their credit card details, give it their mother's maiden name, confirm address, upload a nude selfie, and only then realise that they've been had.</p>

<p>The Internet works at pretty close to the speed of light. You can register a .uk domain and a minute later it's accessible from the other side of the planet. Brilliant for users who want to quickly launch a website. Also brilliant for abusers who want to launch a spam campaign.</p>

<p>By the time enough people have reported the scammers' domain as suspicious, it is too late. In the time it takes for a registrar to disable the domain, or for its name to make its way to the <a href="https://safebrowsing.google.com/">Safe Browsing List</a>, a million messages have already been sent and enough people have handed over their details.</p>

<p>We're told that "<a href="https://en.wikipedia.org/wiki/The_purpose_of_a_system_is_what_it_does">the purpose of a system is what it does</a>". At the moment, the Domain Name System's purpose seems to be a vector for criminals to run scams on people at a terrifyingly high rate.</p>

<h2 id="how-big-is-this-problem"><a href="https://shkspr.mobi/blog/2026/09/the-purpose-of-dns-is-to-spread-scams/#how-big-is-this-problem">How big is this problem?</a></h2>

<p>BIG!</p>

<p>There's a great blog post by Andrew Campling which reports on this startling claim:</p>

<blockquote><p>The study found that at least 10% of all new gTLD domain names registered during the year had subsequently appeared on security blocklists by the time of analysis. It estimated that, taking account of subsequent blocklisting and associated domains not themselves blocklisted, the share of names registered by malicious actors <strong>may be closer to 20%</strong>.</p>

<p><a href="https://labs.ripe.net/author/andrew_campling/dns-abuse-and-criminal-infrastructure-beyond-definitions-and-blocklists/">DNS Abuse and Criminal Infrastructure: Beyond Definitions and Blocklists</a> (emphasis added)</p></blockquote>

<p>That links to a presentation by Interisle which contains some rather shocking statistics (<a href="https://www.icann.org/en/blogs/details/looking-beyond-the-numbers-understanding-malicious-domain-registration-data-10-08-2026-en">albeit with disputed methodology</a>). It looks at <em>generic</em> Top Level Domains (gTLD) - those are things like .com and .fun rather than country code TLDs (ccTLD) like .uk and .de.</p>

<p>It says 85 million new registrations of gTLDs were made in 2025. Of those 8.5 million were added to blocklists by May 2025. It reckons that a 10% abuse rate is the likely floor for these numbers and it's probably closer to 20%. One in five newly registered domains with a gTLD are scams. That's a bloody crisis.</p>

<p>13 TLDs had more than 50% of their registrations blocklisted.</p>

<img src="https://shkspr.mobi/blog/wp-content/uploads/2026/08/gTLDs.webp" alt="Table listing the top 13 generic Top-Level Domains (gTLDs) with the highest percentage of blocklisted, malicious new domains created in 2025. Ranked from highest to lowest blocklist percentage, top entries include .LOCKER (72.9%), .LGBT (72.2%), and .TOWN (70.2%). The table detail includes TLD operators, registration totals, and specific malicious domain metrics." width="1162" height="954" class="aligncenter">

<p>I can understand why .bid and .loan are popular with scammers. But why .mobi?! What did I ever do to you, eh?</p>

<p>Who are the scammers registering these through?</p>

<img src="https://shkspr.mobi/blog/wp-content/uploads/2026/08/registrars.webp" alt="List of registrars. NameCheap, Gname, Dynadot, NameSilo, GoDaddy." width="910" height="390" class="aligncenter">

<p>Ah, our old friends at NameCheap. See <a href="https://shkspr.mobi/blog/2021/05/why-do-scammers-love-namecheap/">Why do scammers love NameCheap?</a></p>

<p>If those five registrars had more effective policies, it might significantly dent the scammers' ability to ply their devious wares. Or they might just move on to other registrars.</p>

<p>As the report points out:</p>

<blockquote><p>suspension rates for blocklisted domains were 7.4% to 16.3%.</p></blockquote>

<p><a href="https://interisle.net/s/FullReport_MaliciousRegistrationsintheDomainNameMarket_2026_rev.pdf">The full report is on the Interisle website</a>.</p>

<h2 id="what-can-be-done"><a href="https://shkspr.mobi/blog/2026/09/the-purpose-of-dns-is-to-spread-scams/#what-can-be-done">What can be done?</a></h2>

<p>I don't know.</p>

<p>In the first instance, it might make sense for registrars to do strong Know Your Customer (KYC) checks on anyone buying a domain. But that stops anyone who wants to anonymously register <code>I-Hate-Nintendo.whatever</code> without risking the wrath of Intellectual Property lawyers.</p>

<p>Also, criminals have access to stolen money and stolen cards. They can convince a hapless mule to register a domain on the criminals' behalf.</p>

<p>Registrars could ask for an escrow payment. Pay €9 for the domain name put €900 in escrow. If your domain appears on a blocklist within the year, you forfeit the money. Criminals with stolen funds are unlikely to care but it would probably put off lots of people from getting a new domain.</p>

<p>There are various banned words and phrases depending on the TLD. For example, <a href="https://shkspr.mobi/blog/2024/07/ss-tld-opening-for-direct-registrations/">South Sudan</a> has a list of political words which they don't want associated with their .ss ccTLD.</p>

<p>But if one gTLD bans a word, a different one might not. A scammer doesn't care if the gTLD is .arse or .elbow - they just want the start of the domain to look legitimate.</p>

<p>Some registrars have strings that they don't allow. In fairness to NameCheap, when I tried to register <code>dwp-payments-gov-uk.pizza</code> it told me that domain was banned. It wouldn't let me get any gTLD with that name.</p>

<p>But all it takes is one registrar to be slightly lax and the scammers get through. Increasing the complexity of the rules is also a hell of a burden on smaller registrars.</p>

<p>Besides, it's pretty easy to get a generic enough looking domain and stick the confusing bit on a subdomain. Here are a clutch mentioned in the report:</p>

<ul>
<li><code>https://gov.uk-dwpaph.bond/uk/</code></li>
<li><code>https://gov.uk-dwpcjh.bond/uk/</code></li>
<li><code>https://gov.uk-dwpclc.bond/uk</code></li>
<li><code>https://gov.uk-dwpclw.bond/uk</code></li>
<li><code>https://gov.uk-dwpclj.bond/uk/</code></li>
</ul>

<p>Perhaps there ought to be a delay before a new domain goes live to allow people to object to it? That would give governments, banks, delivery companies, and a dozen more "important" organisations a right to veto any "dodgy" looking domain.</p>

<p>But suppose someone wants to register <code>gov-uk-stole-my-horse.horse</code> to protest the government's cruel policy of stealing horses - is that a legitimate use of a domain? What if the Darwin Pensioner Divas - a group of elderly singers - want to take payments for their new album of goth/punk covers, can the DPD delivery company veto <code>dpd-payments.music</code>?</p>

<p>Do we want a domain name system where powerful companies control exactly which domains we can register? If I have an idea for a domain on a Friday night do I have to wait until Monday before it can be launched? Are those companies realistically able to parse millions of domains per year and have a low false-positive rate?</p>

<p>All of these things are possible - but all of them come with an impact on legitimate users. To be clear, I don't know what the right answer is.</p>

<h2 id="what-is-icann-doing-about-it"><a href="https://shkspr.mobi/blog/2026/09/the-purpose-of-dns-is-to-spread-scams/#what-is-icann-doing-about-it">What is ICANN doing about it?</a></h2>

<p>Lots! It has been a few years since I've been to an ICANN meeting, but even back then the topic of abuse was high on the agenda. They appear to be looking at ways to coordinate abuse reports between various entities, along with some other policies which should hopefully work.</p>

<p>There are two salient points from <a href="https://hosted-files.sched.co/icann86/b3/TRANSC_I86SQV_Mon08June2026__GNSO-DNS%20Abuse%20Mitigation%20PDP%201%20%281%20of%204%29-en.pdf">one of the discussions held at the recent meeting</a></p>

<blockquote><p>If anybody thinks that in our current age of AI and as we move into different kinds of computing, DNS abuse is going to numerically stay steady and we will have a downward effect on that baseline 2027 number. I'm not sure that that's an accurate assumption. I think it's going to be the other thing, which is […] it's going to be easier to abuse the DNS.</p></blockquote>

<p>And</p>

<blockquote><p>Abusers are going to abuse because it's just too lucrative, because no matter what we do, they will find the way to make profit off of that, and will try to circumvent everything that we do. That is not a reason not to do it, though.</p></blockquote>

<p>Quite!</p>

<p>As I said, I don't know the answer to this. What I do know is, much like <a href="https://shkspr.mobi/blog/2025/08/is-it-possible-to-allow-sideloading-and-keep-users-safe/">Android's app ecosystem being a haven for scammers</a>, DNS is facing a crisis. When trust in a system goes, only chaos follows.</p>

<p>I don't want to live in a world where I have to show my passport and pay thousands of pounds to register a domain which is only available after being vetted by private interests. But I also don't want to live in a world where scammers have effectively no deterrent from abusing millions of people.</p>

<p>The purpose of a system is what it does. I hope DNS's purpose can become less dangerous while still remaining open.</p>
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			</entry>
		<entry>
		<author>
			<name>Terence Eden</name>
							<uri>https://edent.tel/</uri>
						</author>

		<title type="html"><![CDATA[Book Review: The Passing of the Dragon and Other Stories by Ken Liu ★★★★☆]]></title>
		<link rel="alternate" type="text/html" href="https://shkspr.mobi/blog/2026/09/book-review-the-passing-of-the-dragon-and-other-stories-by-ken-liu/" />

		<id>https://shkspr.mobi/blog/?p=74686</id>
		<updated>2026-09-25T21:52:39Z</updated>
		<published>2026-09-05T11:34:47Z</published>
		<category scheme="https://shkspr.mobi/blog" term="Book Review" /><category scheme="https://shkspr.mobi/blog" term="NetGalley" /><category scheme="https://shkspr.mobi/blog" term="Sci Fi" />
		<summary type="html"><![CDATA[This is a gorgeous set of short stories - and a good deal more accessible than some of the heavyweight prose Liu has previously been involved with. Some of the stories contain sentences which are complex jewels to be savoured.  What I particularly like is the way he moves between almost-prosaic Earth-bound stories to the the most extraordinary flights of fancy. One story might be set in a…]]></summary>

					<content type="html" xml:base="https://shkspr.mobi/blog/2026/09/book-review-the-passing-of-the-dragon-and-other-stories-by-ken-liu/"><![CDATA[<img src="https://shkspr.mobi/blog/wp-content/uploads/2026/09/9781035929306.webp" alt="Book cover." width="200" class="alignleft">

<p>This is a gorgeous set of short stories - and a good deal more accessible than some of the heavyweight prose Liu has previously been involved with. Some of the stories contain sentences which are complex jewels to be savoured.</p>

<p>What I particularly like is the way he moves between almost-prosaic Earth-bound stories to the the most extraordinary flights of fancy. One story might be set in a downtown art gallery, the next in the ice-rings of a far-off planet. The creeping feeling of senescence haunts the reader as they flit from story to story.</p>

<p>Much like his full-length novel <a href="https://shkspr.mobi/blog/2025/09/book-review-all-that-we-see-or-seem-by-ken-liu/">All That We See or Seem</a>, Liu has an incredible knack for tapping in to modern fears and weaving tall tales around them. There's a tenderness in all his character - even when a couple of the stories go nowhere, it is still pleasant to spend time in the worlds he has created.</p>

<p>It is, perhaps, missing a cohesive theme - the dragons come and go throughout the stories. Nevertheless, a compelling work chock full of fantastical ideas.</p>

<p>If you're in the mood for a wide and varied selection of stories, this is well worth picking up.</p>

<p>Many thanks to NetGalley for the review copy. Passing of the Dragon is available to buy now.</p>
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			</entry>
		<entry>
		<author>
			<name>Terence Eden</name>
							<uri>https://edent.tel/</uri>
						</author>

		<title type="html"><![CDATA[A reasonably practical guide to validating RFC 9421 HTTP Signatures for ActivityPub in PHP]]></title>
		<link rel="alternate" type="text/html" href="https://shkspr.mobi/blog/2026/09/a-reasonably-practical-guide-to-validating-rfc-9421-http-signatures-for-activitypub-in-php/" />

		<id>https://shkspr.mobi/blog/?p=74429</id>
		<updated>2026-09-04T13:36:29Z</updated>
		<published>2026-09-03T11:34:12Z</published>
		<category scheme="https://shkspr.mobi/blog" term="ActivityBot" /><category scheme="https://shkspr.mobi/blog" term="ActivityPub" /><category scheme="https://shkspr.mobi/blog" term="mastodon" /><category scheme="https://shkspr.mobi/blog" term="php" /><category scheme="https://shkspr.mobi/blog" term="webdev" />
		<summary type="html"><![CDATA[If you&#039;re reading this, you&#039;ve probably been hitting your head against a brick wall trying to parse and decipher the new HTTP Signatures sent by Mastodon and other Fediverse servers.  This is a basic and somewhat incomplete guide to accepting these signatures. I&#039;m sure there are various gotchas, but it works with the signatures I&#039;ve seen in the wild.  Shut Up And Show Me The Code!  OK, wow, no…]]></summary>

					<content type="html" xml:base="https://shkspr.mobi/blog/2026/09/a-reasonably-practical-guide-to-validating-rfc-9421-http-signatures-for-activitypub-in-php/"><![CDATA[<p>If you're reading this, you've probably been hitting your head against a brick wall trying to parse and decipher the new HTTP Signatures sent by Mastodon and other Fediverse servers.</p>

<p>This is a basic and somewhat incomplete guide to accepting these signatures. I'm sure there are various gotchas, but it works with the signatures I've seen in the wild.</p>

<h2 id="shut-up-and-show-me-the-code"><a href="https://shkspr.mobi/blog/2026/09/a-reasonably-practical-guide-to-validating-rfc-9421-http-signatures-for-activitypub-in-php/#shut-up-and-show-me-the-code">Shut Up And Show Me The Code!</a></h2>

<p>OK, wow, no need to be a dick about it! Here's how I validated a real signature that my server received. This requires PHP 8.4 or newer.</p>

<pre><code class="language-php">$verified = openssl_verify(
    data:       '"@method": POST
"@target-uri": https://example.viii.fi/inbox
"content-digest": sha-256=:tFdB/ENGczHMlZMDb66pXoUi2d0OqH2iBHdnN/WV1mc=:
"@signature-params": ("@method" "@target-uri" "content-digest");created=1787780262;keyid="https://mastodon.social/users/Edent#main-key"',
    signature:  base64_decode( "sIfmNsM/Q8iG6AJlne1IkZVjQSVFDEYIPsnoSOXQY+W3Eb4+SOn9o4J5SQmFOP+Jecjf3ioFwUdsrFjAGkUUOHPvSbNWkGKtNuGm+C6r3aI3JBCFGPqX3ITgZYV76CF7JJJ5hPGaG8YH/XdmxVIeFfD3M39FQCncMyyq7xJJvwKKP1mzS5s1vNQie8hbQ9owRjtqvoWcmM9GEYCUHNcMPLjZc+CBrj8sfBbNTYgIFI4UtirOaRJvYymxXjmXuzeVYxQujMjAjgobxQ8QFv0zlYsHk+gS5EYyafpJG9zmfCFSoF9+ZwqKNADmuADbISD9LZIH/bmkPoNXhxaeFPqYog==" ),
    public_key: "-----BEGIN PUBLIC KEY-----\nMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAsYMEs4waqk/6gaS+xn1T\nYygElTtNIFNkBcEdEBMaeoGVhyZiVKtSjJCS4z+X+394PKvcfSTcFILIt2GI2jOB\nHD0M2fFgxc8mmdSdCQkgEh9jF3bFI3kopDvzYf726iioYKlHXKpfPKvFt7EJgKH7\naCtS25NQkek3YUd6y3VBcT3R6Xhze9P3QNoZMIsFXklgXDKj+EllfbUqLf1vxt3s\nmD9ETxy2bJi9FheE0uY2WhARn49XAvwczM5Wzt+zqxVEtgpi5v2+ZZAVKhDnJkiC\nCCuI6hrSnKNIx/5mSlX0a0S5h5d03djrCkYsqmwelu01rhOXP2grsz4BXp0y2wrO\n3QIDAQAB\n-----END PUBLIC KEY-----\n",
    algorithm:  "sha256"
);

echo $verified;
</code></pre>

<p>Copy and paste that into PHP and you should see that <code>$verified</code> is true.</p>

<h2 id="now-explain-the-code"><a href="https://shkspr.mobi/blog/2026/09/a-reasonably-practical-guide-to-validating-rfc-9421-http-signatures-for-activitypub-in-php/#now-explain-the-code">NOW EXPLAIN THE CODE</a></h2>

<p>Say please.</p>

<h2 id="please"><a href="https://shkspr.mobi/blog/2026/09/a-reasonably-practical-guide-to-validating-rfc-9421-http-signatures-for-activitypub-in-php/#please">PLEASE!!!</a></h2>

<p>Along with the message sent to your server, you will have received HTTP headers like this:</p>

<pre><code class="language-_">content-digest: sha-256=:tFdB/ENGczHMlZMDb66pXoUi2d0OqH2iBHdnN/WV1mc=:
signature: sig1=:sIfmNsM/Q8iG6AJlne1IkZVjQSVFDEYIPsnoSOXQY+W3Eb4+SOn9o4J5SQmFOP+Jecjf3ioFwUdsrFjAGkUUOHPvSbNWkGKtNuGm+C6r3aI3JBCFGPqX3ITgZYV76CF7JJJ5hPGaG8YH/XdmxVIeFfD3M39FQCncMyyq7xJJvwKKP1mzS5s1vNQie8hbQ9owRjtqvoWcmM9GEYCUHNcMPLjZc+CBrj8sfBbNTYgIFI4UtirOaRJvYymxXjmXuzeVYxQujMjAjgobxQ8QFv0zlYsHk+gS5EYyafpJG9zmfCFSoF9+ZwqKNADmuADbISD9LZIH/bmkPoNXhxaeFPqYog==:
signature-input: sig1=("@method" "@target-uri" "content-digest");created=1787780262;keyid="https://mastodon.social/users/Edent#main-key"
</code></pre>

<p>The <code>signature-input</code> tells you how to construct a "Signature Base". You have to build a text string which places the various components in the order specified and separated with a newline:</p>

<pre><code class="language-_">"@method": POST
"@target-uri": https://example.viii.fi/inbox
"content-digest": sha-256=:tFdB/ENGczHMlZMDb66pXoUi2d0OqH2iBHdnN/WV1mc=:
"@signature-params": ("@method" "@target-uri" "content-digest");created=1787780262;keyid="https://mastodon.social/users/Edent#main-key"
</code></pre>

<p>Where <code>@method</code> is the HTTP method used to send data to your server (usually <code>GET</code> or <code>POST</code>), and <code>@target-uri</code> is the URl the message was sent to (usually your inbox).</p>

<p>The <code>publicKey</code> is slightly trickier. As you can see, the <code>signature-input</code> ends with <code>keyid="https://mastodon.social/users/Edent#main-key</code></p>

<p>If you make a signed request to that URl, you'll get back an ActivityPub Actor document. It will look something like this:</p>

<pre><code class="language-json">{
  "@context": [
    "https://www.w3.org/ns/activitystreams",
    "https://w3id.org/security/v1",
  ],
  "id": "https://mastodon.social/users/Edent",
  "webfinger": "Edent@mastodon.social",
  "type": "Person",
  "name": "Terence Eden",
  "publicKey": {
    "id": "https://mastodon.social/users/Edent#main-key",
    "owner": "https://mastodon.social/users/Edent",
    "publicKeyPem": "-----BEGIN PUBLIC KEY-----\nMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAsYMEs4waqk/6gaS+xn1T\nYygElTtNIFNkBcEdEBMaeoGVhyZiVKtSjJCS4z+X+394PKvcfSTcFILIt2GI2jOB\nHD0M2fFgxc8mmdSdCQkgEh9jF3bFI3kopDvzYf726iioYKlHXKpfPKvFt7EJgKH7\naCtS25NQkek3YUd6y3VBcT3R6Xhze9P3QNoZMIsFXklgXDKj+EllfbUqLf1vxt3s\nmD9ETxy2bJi9FheE0uY2WhARn49XAvwczM5Wzt+zqxVEtgpi5v2+ZZAVKhDnJkiC\nCCuI6hrSnKNIx/5mSlX0a0S5h5d03djrCkYsqmwelu01rhOXP2grsz4BXp0y2wrO\n3QIDAQAB\n-----END PUBLIC KEY-----\n"
  },
</code></pre>

<p>The <code>publicKeyPem</code> is the string you need. There's no need to convert the <code>\n</code> to literal newlines.</p>

<h2 id="is-that-it"><a href="https://shkspr.mobi/blog/2026/09/a-reasonably-practical-guide-to-validating-rfc-9421-http-signatures-for-activitypub-in-php/#is-that-it">Is that it?</a></h2>

<p>Not quite! All we've done so far is verify the headers. It is possible that these are genuine headers but attached to a fraudulent body.</p>

<p>This takes us back to the header <code>"content-digest": sha-256=:tFdB/ENGczHMlZMDb66pXoUi2d0OqH2iBHdnN/WV1mc=:</code></p>

<p>That says that the body of the message sent has a Base64 encoded SHA256 hash of <code>tFdB/ENGczHMlZMDb66pXoUi2d0OqH2iBHdnN/WV1mc=</code>.</p>

<p>To calculate your own content digest in PHP:</p>

<pre><code class="language-php">$input = file_get_contents( "php://input" );
$digestCalculated = base64_encode(
    hash(
        algo: "sha256",
        data: $input,
        binary: true
    )
);
</code></pre>

<p>Does your digest match the one sent along with the headers? If not, something dodgy is going on.</p>

<h2 id="putting-it-all-together"><a href="https://shkspr.mobi/blog/2026/09/a-reasonably-practical-guide-to-validating-rfc-9421-http-signatures-for-activitypub-in-php/#putting-it-all-together">Putting it all together</a></h2>

<p>The steps are:</p>

<ol>
<li>Get the headers.</li>
<li>Get the body.</li>
<li>From the headers' <code>content-digest</code> extract the algorithm and hash.</li>
<li>Using the body, calculate your own hash using the algorithm from <code>content-digest</code>.</li>
<li>Does your hash match the sent hash? If not, stop. If so, proceed.</li>
<li>From the headers' <code>signature</code> extract the base64 encoded signature.</li>
<li>From the headers' <code>signature-input</code> extract the signature-input string.</li>
<li>From the signature-input string extract the order of the Signature Base.</li>
<li>Construct the Signature Base.</li>
<li>From the signature-input string extract the keyid.</li>
<li>Get the Public Key from the keyid.</li>
<li>Use <code>openssl_verify()</code> to verify the Signature Base and the base64 decoded signature, against the Public Key using SHA256.</li>
</ol>

<p>Note, <a href="https://docs.joinmastodon.org/spec/security/#http-message-signatures">Mastodon <em>only</em> uses SHA256</a>.  I think it should explicitly say which algorithm it is using <a href="https://github.com/mastodon/mastodon/issues/29905#issuecomment-5440336919">and have raised the issue</a>.</p>

<h3 id="in-code-form"><a href="https://shkspr.mobi/blog/2026/09/a-reasonably-practical-guide-to-validating-rfc-9421-http-signatures-for-activitypub-in-php/#in-code-form">In Code Form</a></h3>

<p>This is how you do it in PHP. Please read this carefully as there are some hard-coded assumptions.</p>

<pre><code class="language-php">&lt;?php

//  Validate the Digest.
//  It is the hash of the raw input string, in binary, encoded as base64.

//  The format is content-digest =&gt; &lt;algorithm&gt;=:&lt;base64 encoded hash&gt;:
$digestString = $headers["content-digest"];
//  The Base64 encoding may have multiple `=` at the end. So split this at the first `=`.
$digestData = explode( separator: "=", string: $digestString, limit: 2 );

//  Hashes are in lowercase, but have a `-` in their name.
//  This is not what hash_algos() expects.
$digestAlgorithm = str_replace( search: "-", replace: "", subject: $digestData[0] );

//  The hash is surrounded by `:` characters.
$digestHash = str_replace( search: ":", replace: "", subject: $digestData[1] );

//  Check if the hash algorithm is one known about to PHP.
//  If not, reject and record an error.
if ( !in_array( needle:$digestAlgorithm, haystack: hash_algos() ) ) {
    return false;
}

//  Manually calculate the digest based on the data sent.
$digestCalculated = base64_encode( hash( algo: $digestAlgorithm, data: $input, binary: true ) );

//  Does our calculation match what was sent?
if ( !( $digestCalculated == $digestHash ) ) {
    return false;
}

//  The signature format is signature =&gt; &lt;signature name&gt;=:&lt;base64 encoded hash&gt;:
$signatureString = $headers["signature"];
//  The Base64 encoding may have multiple `=` at the end. So split this at the first `=`.
$signatureData = explode( separator: "=", string: $signatureString, limit: 2 );
$signatureName = $signatureData[0];

//  The signature is surrounded by `:` characters.
$signatureB64 = str_replace( search: ":", replace: "", subject: $signatureData[1] );

//  The signature-input format is complicated!
$signatureInputString = $headers["signature-input"];

//  Get the parameters. Assume there is only one signature.
$signatureParamsString = explode( separator: "=", string: $signatureInputString, limit: 2 )[1];

//  Get the different elements of the signature.
$signatureInputData = explode( separator: ";", string: $signatureInputString );

//  Construct the data.
$signatureInput = [];
foreach( $signatureInputData as $signatureInputParts ) {
    $partsData = explode( separator: "=", string: $signatureInputParts );
    //  Strip quotes from keyid and parentheses from sig1.
    if ( "keyid" == $partsData[0] ) {
        $partsData[1] = str_replace( search: "\"", replace: "", subject: $partsData[1] );
    }

    if ( $signatureName == $partsData[0] ) {
        $partsData[1] = str_replace( search: ["(", ")"], replace: "", subject: $partsData[1] );
    }

    $signatureInput[ $partsData[0] ] = $partsData[1] ;
}

$signatureStructure = $signatureInput[$signatureName];
$signatureKeyID     = $signatureInput["keyid"];

//  Remove quotes.
$signatureStructure = str_replace( search: "\"", replace: "", subject: $signatureStructure );
$signatureStructureData = explode( separator: " ", string: $signatureStructure );

//  https://www.rfc-editor.org/info/rfc9421/#section-2.5
$signatureBase = "";
foreach ( $signatureStructureData as $signatureStructureParts ) {
    if ( "@method" == $signatureStructureParts ) {
        //  https://www.rfc-editor.org/info/rfc9421/#name-method
        $signatureBase .= "\"@method\": " . $_SERVER["REQUEST_METHOD"] . "\n";
    }
    if ( "@target-uri" == $signatureStructureParts ) {
        //  https://www.rfc-editor.org/info/rfc9421/#section-2.2.2
        //  Change the domain name to your own.
        $signatureBase .= "\"@target-uri\": https://EXAMPLE.COM" . $_SERVER["REQUEST_URI"] . "\n";
    }
    if ( "content-digest" == $signatureStructureParts ) {
        $signatureBase .= "\"content-digest\": $digestString\n";
    }
}

//  https://victoronsoftware.com/posts/http-message-signatures/#how-the-signature-is-created
$signatureBase .= "\"@signature-params\": $signatureParamsString";

//  Get the signing user's public key.
//  This is usually in the form `https://example.com/user/username#main-key`
//  This is to differentiate if the user has multiple keys.
//  This may need to be a signed request. You will need to write your own getDataFromURl() function to get the sending user's key.
$userData  = getDataFromURl( $signatureKeyID );
$publicKey = $userData["publicKey"]["publicKeyPem"];

//  Verify the request
$verified = openssl_verify(
    data:       $signatureBase,
    signature:  base64_decode( $signatureB64 ),
    public_key: $publicKey,
    algorithm:  $digestAlgorithm
);

//  Convert the result to boolean.
if ( $verified === 1 ) {
    $verified = true;
} elseif ( $verified === 0 ) {
    $verified = false;
} else {
    $verified = null;
}

return $verified;
</code></pre>

<h2 id="further-reading"><a href="https://shkspr.mobi/blog/2026/09/a-reasonably-practical-guide-to-validating-rfc-9421-http-signatures-for-activitypub-in-php/#further-reading">Further Reading</a></h2>

<ul>
<li><a href="https://www.rfc-editor.org/info/rfc9421/">RFC 9421 HTTP Message Signatures</a></li>
<li><a href="https://victoronsoftware.com/posts/http-message-signatures/">Understanding HTTP message signatures: A developer's guide</a></li>
<li><a href="https://www.otoroshi.io/docs/tutorials/http-message-signatures-rfc9421/">Sign and verify HTTP messages (RFC 9421)</a></li>
<li><a href="https://darutk.medium.com/verification-of-http-message-signatures-501bbdc7dfec">Verification of HTTP Message Signatures</a></li>
<li><a href="https://github.com/macgirvin/HTTP-Message-Signer">HTTP-Message-Signer in PHP</a></li>
</ul>

<h2 id="thanks-to-nlnet"><a href="https://shkspr.mobi/blog/2026/09/a-reasonably-practical-guide-to-validating-rfc-9421-http-signatures-for-activitypub-in-php/#thanks-to-nlnet">Thanks to NLnet</a></h2>

<p>This blog post was funded in part by the work I'm doing for my NLnet NGI0 grant. Thanks!</p>

<p><a href="https://nlnet.nl/project/ActivityBot/"><img src="https://shkspr.mobi/blog/wp-content/uploads/2026/08/NGI-logos.webp" alt="NLnet logo." width="900" height="200" class="aligncenter"></a></p>
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      "id": "https://shkspr.mobi/blog/?p=76031",
      "title": "Gadget Review: Una Watch ★★★★☆",
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      "published": "2026-10-02T11:34:48.000Z",
      "updated": "2026-10-01T07:47:47.000Z",
      "content": "<p>I've never been a huge fan of smart watches. My <a href=\"https://shkspr.mobi/blog/2025/08/i-bought-a-16-smartwatch-just-because-it-used-usb-c/\">£16 smartwatch</a> is basically fine, but the OS is closed source and there's no way to add new functionality.  Previously I had the <a href=\"https://shkspr.mobi/blog/2023/06/review-watchy-an-eink-watch-full-of-interesting-compromises/\">eInk Watchy</a> which was a pain to use and really poorly designed.  Even back in 2014 I was bemoaning the design compromises in the <a href=\"https://shkspr.mobi/blog/2014/11/disassembling-the-mykronoz-zewatch-smart-watch/\">MyKronoz ZeWatch Smart Watch</a>.</p>\n\n<p>So why did I pick up the Una Watch?</p>\n\n<p>Firstly, the Una Watch is designed in Scotland <del>from girders</del>, and it's always nice to support local businesses.</p>\n\n<p>Secondly, as a <a href=\"https://shkspr.mobi/blog/2026/07/im-a-usb-c-maximalist/\">USB-C Maximalist</a> I want gadgets which can plug in to the same cables as all my other toys. No magnetic pucks here!</p>\n\n<p>Thirdly, it is (almost) <a href=\"https://unawatch.com/pages/open-source\">completely open source</a>.</p>\n\n<p>Finally, it is repairable. You can easily unscrew it to replace the components. As my cheap smartwatch's dial has died after 12 months of use, that's a pretty compelling proposition!</p>\n\n<p>Let's put it through its paces!</p>\n\n<h2 id=\"first-impressions\"><a href=\"https://shkspr.mobi/blog/2026/10/gadget-review-una-watch/#first-impressions\">First Impressions</a></h2>\n\n<p>I bought mine second hand (yay for sustainability) and it arrived with a flat battery. The first charge from 0-100% took a little over an hour. My USB-C power monitor showed it taking in about 5V and 0.17 amps.</p>\n\n<img src=\"https://shkspr.mobi/blog/wp-content/uploads/2026/09/Charging.webp\" alt=\"Power monitor showing 0.84W.\" width=\"1024\" height=\"576\" class=\"aligncenter\">\n\n<p>It happily charged from a PD plug, but didn't get any faster than about 0.84W. Basically, I can fully charge it on most public transport in London.</p>\n\n<p>The time seemed accurate, there were options to play about with, the vibrations for notifications were easy to feel. There is an option to make it beep with every button press - I turned that off sharpish!</p>\n\n<h2 id=\"disclaimer\"><a href=\"https://shkspr.mobi/blog/2026/10/gadget-review-una-watch/#disclaimer\">Disclaimer</a></h2>\n\n<p>I am <em>not</em> <a href=\"https://shkspr.mobi/blog/2026/09/are-you-a-smartwatch-power-user/\">a smartwatch power user</a>. I'm not using this to minutely track all my exercise or calculate if my heart is going to explode.  I don't need cm level precision of my GPS. I didn't sync this with Strava or anything else.</p>\n\n<h2 id=\"apps\"><a href=\"https://shkspr.mobi/blog/2026/10/gadget-review-una-watch/#apps\">Apps</a></h2>\n\n<p>The official Android app (which, sadly, isn't Open Source) worked fine on GrapheneOS. It found the watch, updated its GPS almanac, and let me browse the app store & install apps. Obviously early days, but there are a variety of community developed apps to play with.</p>\n\n<img src=\"https://shkspr.mobi/blog/wp-content/uploads/2026/09/apps.webp\" alt=\"List of apps.\" width=\"504\" height=\"728\" class=\"aligncenter\">\n\n<p>Annoyingly the watch needs to be restarted after every app is installed - but that only take a handful of seconds.</p>\n\n<img src=\"https://shkspr.mobi/blog/wp-content/uploads/2026/09/Restart-watch.webp\" alt=\"Message telling me the watch needs to restart.\" width=\"504\" height=\"640\" class=\"aligncenter\">\n\n<p>There are some <em>strange</em> error messages.</p>\n\n<img src=\"https://shkspr.mobi/blog/wp-content/uploads/2026/09/error-message.webp\" alt=\"birthday must be a valid ISO 8601 date string country must be a valid ISO31661 Alpha2 code.\" width=\"504\" height=\"426\" class=\"aligncenter\">\n\n<p>That isn't the sort of message which should be shown to users.</p>\n\n<p>But, on the plus side, you can install Doom!</p>\n\n<img src=\"https://shkspr.mobi/blog/wp-content/uploads/2026/09/Doom.webp\" alt=\"App store listing showing Doom on the watch.\" width=\"504\" height=\"550\" class=\"aligncenter\">\n\n<h2 id=\"the-screen\"><a href=\"https://shkspr.mobi/blog/2026/10/gadget-review-una-watch/#the-screen\">The Screen</a></h2>\n\n<p>Oddly for a modern smartwatch, the screen stays on <em>all the time!</em> But this isn't some power-hungry OLED, nor is it static eInk. Instead it is a <a href=\"https://www.andersdx.com/memory-in-pixel-displays/\">memory in pixel</a> display - black background with orange, blue, and white pixels.  The backlight remains off most of the time and is easy enough to see in daylight. It is <em>slightly</em> reflective - but not too bad.</p>\n\n<img src=\"https://shkspr.mobi/blog/wp-content/uploads/2026/09/Reflective.webp\" alt=\"Watch showing notifications, there is a bit of a reflection.\" width=\"1024\" height=\"576\" class=\"aligncenter\">\n\n<p>Note the <code>??</code> on the notifications - more on that later.</p>\n\n<p>Annoyingly, there's no \"raise wrist to light\" option. You have to interact with the watch to get the screen on. The accelerometer should allow this functionality - so perhaps it just needs to be activated in the firmware? It is bright enough to see in the dark, but not so bright it will dazzle you or people nearby.</p>\n\n<p>There's no touchscreen - instead there are four buttons around the face. Up, down, select, back. I did find myself repeatedly jabbing at the screen to no avail.</p>\n\n<p>So, to light it, press the back button or hold one of the other buttons.</p>\n\n<p>The colour scheme is pleasant enough. I miss having a full colour display so I can see a photo of my wife whenever I glance at the screen. But the low power usage can't be argued with.</p>\n\n<h2 id=\"notifications\"><a href=\"https://shkspr.mobi/blog/2026/10/gadget-review-una-watch/#notifications\">Notifications</a></h2>\n\n<p>I couldn't get notifications working at first. The app just refused to let me toggle them on. Eventually I found an app in the app-store which claimed to enable them. That didn't work either.</p>\n\n<p>Unpairing, repairing, and reinstalling the app made them spring to life.</p>\n\n<p>There's no notification history. Once you've clicked to read it, that's it. Gone forever. Considering this has 4GB storage, that's an odd decision.</p>\n\n<p>Some of the notifications were slightly corrupt - showing question marks in place of (I assume) esoteric Unicode.</p>\n\n<img src=\"https://shkspr.mobi/blog/wp-content/uploads/2026/09/Question-Mark-notification.webp\" alt=\"A notification on screen with a question mark before the user's name.\" width=\"1024\" height=\"768\" class=\"aligncenter\">\n\n<p>There's no way to customise the vibrate pattern - so everything \"feels\" the same on your wrist.</p>\n\n<p>At the moment, the Una Watch sends <em>every</em> notification to your phone. You can't tell it to ignore certain WhatsApp groups, or only allow text messages from your spouse.  The only way to get fine-grained notifications is with a third-party app like…</p>\n\n<h2 id=\"gadgetbridge\"><a href=\"https://shkspr.mobi/blog/2026/10/gadget-review-una-watch/#gadgetbridge\">Gadgetbridge</a></h2>\n\n<p>You're not tied to the official app. <a href=\"https://gadgetbridge.org/gadgets/wearables/una/\">Gadgetbridge support is excellent</a>. There are a few things missing (you can't install apps or set alarms) - but if you want to measure your heart rate, send notifications, etc you'll be fine.</p>\n\n<h2 id=\"linux-compatibility\"><a href=\"https://shkspr.mobi/blog/2026/10/gadget-review-una-watch/#linux-compatibility\">Linux Compatibility</a></h2>\n\n<p>The Una Watch plugs in to USB-C and shows up as 3.5GB of exFAT formatted storage.</p>\n\n<img src=\"https://shkspr.mobi/blog/wp-content/uploads/2026/10/Una-Filesystem.webp\" alt=\"Filesystem view showing various JSON files.\" width=\"500\" height=\"649\" class=\"aligncenter\">\n\n<p>You can manually edit the JSON files if you like. I think you can copy off your workout data. Or you can just use it as portable storage.</p>\n\n<p>Under <code>lsusb</code> it describes itself as <code>0483:52a4 STMicroelectronics UNA Watch</code></p>\n\n<h2 id=\"battery-life\"><a href=\"https://shkspr.mobi/blog/2026/10/gadget-review-una-watch/#battery-life\">Battery Life</a></h2>\n\n<p>After a full day of use the battery was at around 95% - that was with a bit of GPS, several notifications, heart rate monitoring, step counting, and a bunch of fiddling. With more GPS use, that's going to be heavier on the battery.</p>\n\n<p>But the joy of USB-C is that I can thwack in the same cable as I use for all my other gadgets. I can even plug it into my phone and leach a bit of power from there.</p>\n\n<h2 id=\"development\"><a href=\"https://shkspr.mobi/blog/2026/10/gadget-review-una-watch/#development\">Development</a></h2>\n\n<p>The watch comes will a full <a href=\"https://github.com/UNAWatch/una-sdk\">Open Source SDK</a> including lots of assets. There are several tutorials and a friendly community board.</p>\n\n<p>Of course, everything has to be done in C++ - an accurs'd language which I learned in the last century and wish I'd forgotten.</p>\n\n<p>Annoyingly, the <a href=\"https://github.com/UNAWatch/una-sdk/blob/main/Docs/sdk-setup.md\">TouchGFX GUI designer</a> only works in Windows.</p>\n\n<p>I'm going to try to build my own watch faces and a few niche apps.</p>\n\n<h2 id=\"downsides\"><a href=\"https://shkspr.mobi/blog/2026/10/gadget-review-una-watch/#downsides\">Downsides</a></h2>\n\n<p>There are a few things this watch <em>doesn't</em> do - some of these may be deal-breakers for you, but weren't for me.</p>\n\n<ul>\n<li>No payments. There's no tap-to-pay, NFC, or anything like that.</li>\n<li>No microphone. You cannot speak into your Una Watch or take calls on it.</li>\n<li>No speaker. There's a little buzzer which can make squeaks and squawks - but you won't be playing your music through it.</li>\n<li>While the apps and SDK are fully open, the firmware isn't (yet).</li>\n<li>Can't reply to notifications.</li>\n<li>No maps or directions (yet).</li>\n<li>Step counter only shows the full day - no hour-by-hour view.</li>\n</ul>\n\n<p>Some of these things can and will be fixed in software. Others are limitations of the hardware.</p>\n\n<h2 id=\"final-thoughts\"><a href=\"https://shkspr.mobi/blog/2026/10/gadget-review-una-watch/#final-thoughts\">Final Thoughts</a></h2>\n\n<p>The Una Watch has dropped in price to £180. I grabbed mine 2nd hand from eBay for £120. At either price, it's decent value <em>if</em> you're happy to play with alpha / beta quality technology.</p>\n\n<p>If you're a serious athlete, you'll probably want a more expensive and polished experience. If you are tied into the Apple or Google ecosystems, you'll probably want one of their watches.</p>\n\n<p>If you like tinkering, want to experiment with new technology, or simply want to support a British company trying to build something open - then this is the watch for you. Yes, there are some rough edges, but I fundamentally believe that technology should be Open Source, repairable, and give control to its users.</p>\n<img src=\"https://shkspr.mobi/blog/wp-content/themes/edent-wordpress-theme/info/okgo.php?ID=76031&HTTP_REFERER=Atom\" alt width=\"1\" height=\"1\" loading=\"eager\">",
      "image": null,
      "media": [],
      "authors": [
        {
          "name": "Terence Eden",
          "email": null,
          "url": "https://edent.tel/"
        }
      ],
      "categories": [
        {
          "label": "gadget",
          "term": "gadget",
          "url": "https://shkspr.mobi/blog"
        },
        {
          "label": "review",
          "term": "review",
          "url": "https://shkspr.mobi/blog"
        },
        {
          "label": "UnaWatch",
          "term": "UnaWatch",
          "url": "https://shkspr.mobi/blog"
        },
        {
          "label": "watch",
          "term": "watch",
          "url": "https://shkspr.mobi/blog"
        }
      ]
    },
    {
      "id": "https://shkspr.mobi/blog/?p=74267",
      "title": "Are you a smartwatch \"power user\"?",
      "description": "What do you use your smartwatch for?  A few weeks ago, I overheard a conversation between someone on the Pixel Watch team and a woman I know. He was quizzing her at a party about her Pixel watch and what features she used. He'd ignored me when I said I had a non-Google watch.  She thought for a moment and said, other than telling the time, all she used were pretty much the step counter and…",
      "url": "https://shkspr.mobi/blog/2026/09/are-you-a-smartwatch-power-user/",
      "published": "2026-09-30T11:34:26.000Z",
      "updated": "2026-09-28T09:40:08.000Z",
      "content": "<p>What do you use your smartwatch for?</p>\n\n<p>A few weeks ago, I overheard a conversation between someone on the Pixel Watch team and a woman I know. He was quizzing her at a party about her Pixel watch and what features she used. He'd ignored me when I said I had <a href=\"https://shkspr.mobi/blog/2025/08/i-bought-a-16-smartwatch-just-because-it-used-usb-c/\">a non-Google watch</a>.  She thought for a moment and said, other than telling the time, all she used were pretty much the step counter and contactless payments. He looked a bit crestfallen at his impromptu user-research participant and somewhat dismissively sneered, \"Well, you're not exactly a power user, are you?\"</p>\n\n<!-- \n👋👋👋👋👋👋👋👋👋\nWelcome to Comment Club! This content is only available to people who read my HTML comments. \n\nHonestly, this guy was *such* an arse. Really spoiled an otherwise lovely party. Like, I don't mind talking about people's work - but it seemed that was the only thing he was interested in talking about. He also seemed genuinely offended that I'd bought a non-Google watch and didn't want to hear why I liked it. Oh well, his loss!\n\nOK, the three rules of comment club are…\n\n1. You must not tell anyone about Comment Club - let them find out about it themselves.\n2. You *must* add some Comment Club Content to at least one of your blog posts. Doesn't have to be much, just a little note will do.\n3. You should drop an email to anyone whose comments you've read. Start by sending me a friendly message at comment.club@shkspr.mobi\n\nKeep looking out for more comments in future blog posts 😃\n\nTTFN.\n-->\n\n<p>I'm trying to imagine what being a \"power user\" of a watch is like. Can anyone enlighten me?</p>\n\n<p>I think smart-watches are much like Alexa. What the user <em>wants</em> to do with it is almost totally at odds with what the company is selling. Alexæ are mostly kitchen timers, song players, and light switches. No one is a \"power user\" constantly installing skills and using it for anything which increases the product team's engagement metrics.</p>\n\n<p>The same is probably true of watches. Alerts are nifty - but cumbersome for replies. The health stuff is useful - but only for a subset of users. Seeing the time is great - but if the battery lasts less than a week, who wants to keep that screen on?</p>\n\n<p>People use watches because they are moderately more convenient to carry than the giant phones we have nowadays.</p>\n\n<p>Back when mobile phones were new, exciting, and made a feature of being tiny, I was working for a network operator and trying to come up with reasons for people to use our brand-new 3G network. All the research we had showed that people used their phones for exactly three things:</p>\n\n<ol>\n<li>Voice calls</li>\n<li>Text messages</li>\n<li>A third thing</li>\n</ol>\n\n<p>That \"3rd thing\" was varied. For some it was playing snake, for others it was a calendar, and a few took photos. But almost no-one used their phone beyond the basics. They weren't investigating the sub-menus, nor were they using most of their device's capability unless it was heavily advertised to them (ringtones, basically).</p>\n\n<p>It took the industry a <em>huge</em> amount of effort to get people to actually use their phones for more than calls and texts. Part of that was bigger screens with enticing icons (<a href=\"https://shkspr.mobi/blog/2012/04/give-customers-an-elevator-pitch-for-your-app/\">although users will always be reluctant to click mysterious icons</a>). Another part was that phones became genuinely useful. But perhaps the biggest change, I think, is that phones became <em>easy to use</em>.</p>\n\n<p>Watches have tiny screens. You can only get a few words of a message on there. Icons are tiny and hard to reliably tap. Swiping away at your wrist or fiddling with a crown is a faff. Talking into your wrist makes you look like a prat. Interacting with a smartwatch is <strong>annoying</strong>. Why would anyone want to spend more time using it than is strictly necessary?</p>\n\n<p>I'm sure there are some people out there browsing the web on their wrist, and sending endless voice-notes to their AI assistant, and setting up complex travel plans by tapping their nose on the screen, and installing new watch faces which always point to the nearest Dignitas clinic, and seeing what their heart-rate did during that last run, and tracking whether their menstrual cycle is synced to the phases of the moon, and hoping that tripping on the stairs didn't send an alert to the emergency services, and whatever else the team has cooked up to show that they're still innovating.</p>\n\n<p>But I'll bet those \"power users\" are vastly outnumbered by people who are using a smartwatch for the limited set of actions which are useful to them; not to the manufacturer.</p>\n\n<p>Perhaps the real power users have is the power to use a device on their own terms?</p>\n<img src=\"https://shkspr.mobi/blog/wp-content/themes/edent-wordpress-theme/info/okgo.php?ID=74267&HTTP_REFERER=Atom\" alt width=\"1\" height=\"1\" loading=\"eager\">",
      "image": null,
      "media": [],
      "authors": [
        {
          "name": "Terence Eden",
          "email": null,
          "url": "https://edent.tel/"
        }
      ],
      "categories": [
        {
          "label": "android",
          "term": "android",
          "url": "https://shkspr.mobi/blog"
        },
        {
          "label": "gadgets",
          "term": "gadgets",
          "url": "https://shkspr.mobi/blog"
        },
        {
          "label": "usability",
          "term": "usability",
          "url": "https://shkspr.mobi/blog"
        },
        {
          "label": "watch",
          "term": "watch",
          "url": "https://shkspr.mobi/blog"
        }
      ]
    },
    {
      "id": "https://shkspr.mobi/blog/?p=73671",
      "title": "Book Review: Bobiverse Books 1-3 by Dennis E. Taylor ★★★☆☆",
      "description": "Like sticky popcorn, this is a moreish but ultimately unsatisfying set of stories. After I flamed out of Dungeon Crawler Carl, someone suggested I try this series. I can see why! It's campy sci-fi fun, with enough tropes to keep you chuckling and enough tension to keep you turning the pages.    Bob's brain is uploaded to a computer post-mortem. Awoken in a dystopian future, he has to pilot a…",
      "url": "https://shkspr.mobi/blog/2026/09/book-review-bobiverse-books-1-3-by-dennis-e-taylor/",
      "published": "2026-09-28T11:34:52.000Z",
      "updated": "2026-09-26T12:28:34.000Z",
      "content": "<img src=\"https://shkspr.mobi/blog/wp-content/uploads/2026/08/bobiverse.webp\" alt=\"Book covers for the Bobiverse series.\" width=\"275\" height=\"225\" class=\"alignleft size-full wp-image-73672\">\n\n<p>Like sticky popcorn, this is a moreish but ultimately unsatisfying set of stories. After I flamed out of <a href=\"https://shkspr.mobi/blog/2026/07/book-review-dungeon-crawler-carl-by-matt-dinniman/\">Dungeon Crawler Carl</a>, someone suggested I try this series. I can see why! It's campy sci-fi fun, with enough tropes to keep you chuckling and enough tension to keep you turning the pages.</p>\n\n<!-- \n👋👋👋👋👋👋👋👋👋\nWelcome to Comment Club! This content is only available to people who read my HTML comments. \n\nI kinda hate how quickly I devoured these books. They're sort of like a bowl of bland potato snacks which, nevertheless, you find yourself emptying into your gullet. There are so many *good* sci-fi books that I have no idea why I fixated on these? \n\nYou are required to obey the three rules of comment club - which are…\n\n1. You must not tell anyone about Comment Club - let them find out about it themselves.\n2. You *must* add some Comment Club Content to at least one of your blog posts. Doesn't have to be much, just a little note will do.\n3. You should drop an email to anyone whose comments you've read. Start by sending me a friendly message at comment.club@shkspr.mobi\n\nKeep your eyes peeled for more comments in future blog posts 😃\n\nTTFN.\n-->\n\n<p>Bob's brain is uploaded to a computer post-mortem. Awoken in a dystopian future, he has to pilot a spaceship to strange new worlds, put right what once went wrong, and hoping The Force will be with him, always. Oh, and he repeatedly clones himself. Creating a universe populated with Bobs (a \"Bobiverse\" if you will)</p>\n\n<p>It's your standard \"only I, a slightly geeky guy with lots of pop-culture knowledge, can save the world\" fare which is beloved by slightly geeky guys everywhere who think they're smarter than all those normies just because they can recite the list of Hugo winners alphabetically.</p>\n\n<p>Like <a href=\"https://shkspr.mobi/blog/2015/09/what-i-read-on-my-holidays/\">Ready Player One</a> it throws in as many quips and catchphrases as the plot will bear. Unlike Cline's work, it never really commits to them, so you end up with a scattering of Monty Python, Star Wars, and the X-Files without an overall theme developing.</p>\n\n<p>And, in keeping with Andy Weir's The Martian, it's all just one guy sciencing the shit out of the problem. Except that lots of the science is sort of hand-waved away with \"and then I 3D printed a thing\".</p>\n\n<p>Similar to both those books is an almost total lack of female characters. The ones that are in the first two are either plot-points or harridans. By the third there's a love interest who is <em>slightly</em> more rounded, and a couple of other incidentals, but offset against yet another woman who just can't appreciate the \"genius\" of Bob.</p>\n\n<p>It's all good page turning fun other than the fact that Bob is a <em>total</em> cretin. He begins a slow descent into fascist dictator and barely even comments on it. He spies, carries out extra-judicial killings, and meddles in politics to his own advantage. At no point does the text ever really engage with the fact that <strong>Bob is a monster</strong>.</p>\n\n<p>The character rarely reflects on whether his behaviour meets the moral standard he expects of others. He bemoans the aliens who are destroying entire ecosystems while simultaneously wiping out whole species himself. At times he is a conniving bully and reacts badly to anyone who pushes back against the ineffable will of Bob.</p>\n\n<p>The jumping back-and-forth between the different Bobs is a bit frustrating, a bit like flicking between TV channels. I wish each story strand were allowed some space to develop - but instead it's one chapter of this planet, then one chapter of another, before (eventually) circling back.</p>\n\n<p>Annoyingly, <a href=\"http://dennisetaylor.org/wheres-the-whatever-version/#WhereEpub\">the books are only available on Amazon Kindle</a>. They're not on any other platform or library. I'm grateful to the friend who lent me their copies. I binged the first three but, without any indication that Bob will mature as a character or face a reckoning for his egregious actions, that's where I stopped.</p>\n<img src=\"https://shkspr.mobi/blog/wp-content/themes/edent-wordpress-theme/info/okgo.php?ID=73671&HTTP_REFERER=Atom\" alt width=\"1\" height=\"1\" loading=\"eager\">",
      "image": null,
      "media": [],
      "authors": [
        {
          "name": "Terence Eden",
          "email": null,
          "url": "https://edent.tel/"
        }
      ],
      "categories": [
        {
          "label": "Book Review",
          "term": "Book Review",
          "url": "https://shkspr.mobi/blog"
        },
        {
          "label": "Sci Fi",
          "term": "Sci Fi",
          "url": "https://shkspr.mobi/blog"
        }
      ]
    },
    {
      "id": "https://shkspr.mobi/blog/?p=75993",
      "title": "Gig Review: Public Service Broadcasting's Race For Space at Alexandra Palace ★★★★⯪",
      "description": "Ahhh! PSB's RFS! A delightfully indulgent soundscape of melodic wonder, performed here on its 10th (ish) anniversary. Is it really nostalgia if an album is only a decade old? It feels like it has been in the air forever.    For something which is seemingly made up of samples, it would have been easy for them to half-arse it and basically just play the CD. Instead we got a full band, guest…",
      "url": "https://shkspr.mobi/blog/2026/09/gig-review-public-service-broadcastings-race-for-space-at-alexandra-palace/",
      "published": "2026-09-27T11:34:08.000Z",
      "updated": "2026-09-27T09:05:44.000Z",
      "content": "<p>Ahhh! PSB's RFS! A delightfully indulgent soundscape of melodic wonder, performed here on its 10th (ish) anniversary. Is it really nostalgia if an album is only a decade old? It feels like it has been in the air forever.</p>\n\n<img src=\"https://shkspr.mobi/blog/wp-content/uploads/2026/09/On-Stage.webp\" alt=\"The band on stage with giant projections behind them.\" width=\"2048\" height=\"1542\" class=\"aligncenter\">\n\n<p>For something which is seemingly made up of samples, it would have been easy for them to half-arse it and basically just play the CD. Instead we got a full band, guest singers, and 360° video projection,</p>\n\n<img src=\"https://shkspr.mobi/blog/wp-content/uploads/2026/09/Laser-Display.webp\" alt=\"Flight controls projected above the audience.\" width=\"2048\" height=\"1152\" class=\"aligncenter\">\n\n<p>Oh, also a disco Sputnik flying over the crowd!</p>\n\n<img src=\"https://shkspr.mobi/blog/wp-content/uploads/2026/09/Disco-Sputnik.webp\" alt=\"A large model Sputnik covered in lights.\" width=\"2048\" height=\"1152\" class=\"aligncenter\">\n\n<p>Simply magical! As were the indoor fireworks.</p>\n\n<img src=\"https://shkspr.mobi/blog/wp-content/uploads/2026/09/Fireworks.webp\" alt=\"Sparks shooting upwards from the stage.\" width=\"2048\" height=\"1152\" class=\"aligncenter\">\n\n<p>I might quibble a little with their song choices (no Gagarin!) but hearing the crowd repeatedly scream \"GO!\" was magnificent.</p>\n\n<p>Ally Pally isn't a raked venue, so the video projection of the band was most welcome. An excellent gig in a splendid location.</p>\n\n<h2 id=\"pre-show-and-post-show\"><a href=\"https://shkspr.mobi/blog/2026/09/gig-review-public-service-broadcastings-race-for-space-at-alexandra-palace/#pre-show-and-post-show\">Pre-show and Post-show</a></h2>\n\n<p>As I've written about before, <a href=\"https://shkspr.mobi/blog/2024/12/the-art-of-the-pre-show-and-post-show/\">the art of the Pre-Show and Post-Show</a> is vital for getting people to pay for events outside of their homes. Right now I can stream all the music in the world for a year for about the same price as a couple of gig tickets.  Why should I freeze my arse off outside, paying stupid money for mass-produced lager, when I could be at home?</p>\n\n<p>PSB kept up a constant stream of emails talking about the gig. Not an overwhelming amount, just letting people peek behind the curtain of organising it, giving helpful information about logistics, and letting us know about merchandise which was available.</p>\n\n<p>Crucially, they also gave us stage timings for them and their support act! How many times have you turned up on time to a gig only to spend an hour listening to some crap DJ before the crew even started setting up the stage? PSB treat their fans with respect.</p>\n\n<p>Ally Pally isn't a venue I've been to before. It was well laid out with decent toilet provision - including a big block of portaloos at the back of the hall. The beer prices weren't ruinous, but I kind of resented paying £15 for a veggie hotdog and a handful of chips.</p>\n\n<p>Some venues seem to think that screaming at punters to open their bags will make for an enjoyable visit. Here the security staff were polite and not overly officious. Water bottles were allowed in with a cheery wave.</p>\n\n<p>Post show - although the train stations are downhill, there were several buses waiting to take punters directly back. That's a perfect way of treating guests at your venue - ensuring that they get home safe and sound.</p>\n<img src=\"https://shkspr.mobi/blog/wp-content/themes/edent-wordpress-theme/info/okgo.php?ID=75993&HTTP_REFERER=Atom\" alt width=\"1\" height=\"1\" loading=\"eager\">",
      "image": null,
      "media": [],
      "authors": [
        {
          "name": "Terence Eden",
          "email": null,
          "url": "https://edent.tel/"
        }
      ],
      "categories": [
        {
          "label": "gig",
          "term": "gig",
          "url": "https://shkspr.mobi/blog"
        },
        {
          "label": "review",
          "term": "review",
          "url": "https://shkspr.mobi/blog"
        }
      ]
    },
    {
      "id": "https://shkspr.mobi/blog/?p=74960",
      "title": "No errors, no warnings, no gods, no masters - HTML Purity is a Fetish",
      "description": "\"The problem with defending the purity of the HyperText Markup Language is that HTML is about as pure as a cribhouse whore. The standard doesn't just borrow concepts from better languages; on occasion, HTML has pursued other programming languages down alleyways to beat them unconscious and rifle their pockets for new syntax.\"    Englitch is an pretty goode langwidge. even you no grok all the…",
      "url": "https://shkspr.mobi/blog/2026/09/no-errors-no-warnings-no-gods-no-masters-html-purity-is-a-fetish/",
      "published": "2026-09-26T11:34:02.000Z",
      "updated": "2026-09-26T12:24:48.000Z",
      "content": "<p>\"The problem with defending the purity of the HyperText Markup Language is that HTML is about as pure as a cribhouse whore. The standard doesn't just borrow concepts from better languages; on occasion, HTML has pursued other programming languages down alleyways to beat them unconscious and rifle their pockets for new syntax<sup id=\"fnref:soz\"><a href=\"https://shkspr.mobi/blog/2026/09/no-errors-no-warnings-no-gods-no-masters-html-purity-is-a-fetish/#fn:soz\" class=\"footnote-ref\" title=\"With the appropriate amount of apologies to James Nicoll\" role=\"doc-noteref\">0</a></sup>.\"</p>\n\n<!-- \n👋👋👋👋👋👋👋👋👋\nWelcome to Comment Club! This content is only available to people who read my HTML comments.\n\nAm I being too harsh in calling technical purity a fetish? I don't think so. But I guess I would say that wouldn't I? My Kink *Is* My Kink And That's OK.\n\nDon't forget, the three rules of comment club are…\n\n1. You must not tell anyone about Comment Club - let them find out about it themselves.\n2. You *must* add some Comment Club Content to at least one of your blog posts. Doesn't have to be much, just a little note will do.\n3. You should drop an email to anyone whose comments you've read. Start by sending me a friendly message at comment.club@shkspr.mobi\n\nKeep your eyes peeled for more comments in future blog posts 😃\n\nTTFN.\n-->\n\n<p>Englitch is an pretty goode langwidge. even you no grok all the pacific bits you got the jist & the splelling & grandma dont mattr to much.</p>\n\n<p>HTML is much the same. You can write utterly malformed, derranged, non-standards complaint HTML and most browsers will just say \"Yeah, sure, whatever dawg!\" and render it adequately. Take a look at the source code for <a href=\"https://www.todepond.com/\">TodePond</a> - a lovely website but some of the most abused HTML I've seen.</p>\n\n<p>There's a brilliant blog post by Jens Oliver Meiert which looks at whether HTML validity is seen as a priority for major sites. Basically, no.</p>\n\n<blockquote><p>It’s time for the annual analysis of how much of the HTML code in the field is error-free and valid. The short version: 1% of the most-frequented sites on this planet uses valid HTML—and 99% don’t.</p>\n\n<p><a href=\"https://meiert.com/blog/html-conformance-2026/\">2 of the Global Top 200 Websites Use Valid HTML</a></p></blockquote>\n\n<p>iS ThAt A pRoBlEm????</p>\n\n<p>My site is proudly HTML Valid. Run it through the <a href=\"https://validator.w3.org/nu/?doc=https%3A%2F%2Fshkspr.mobi%2Fblog%2F\">HTML Validator</a> or the <a href=\"https://validator.schema.org/#url=https%3A%2F%2Fshkspr.mobi%2Fblog\">Schema.org Validator</a> and you'll see that it is <em>fucking perfect!</em> Same with my <a href=\"https://validator.w3.org/feed/check.cgi?url=https%3A%2F%2Fshkspr.mobi%2Fblog%2Ffeed\">RSS Feed</a> and <a href=\"https://validator.w3.org/feed/check.cgi?url=https%3A%2F%2Fshkspr.mobi%2Fblog%2Ffeed%2Fatom\">Atom Feed</a>. Not so much as an advisory bit of info, a couched warning, or a sternly worded suggestion<sup id=\"fnref:4now\"><a href=\"https://shkspr.mobi/blog/2026/09/no-errors-no-warnings-no-gods-no-masters-html-purity-is-a-fetish/#fn:4now\" class=\"footnote-ref\" title=\"At the time of writing. Who knows what batshit bugs I'll accidentally include in the future 🙃\" role=\"doc-noteref\">1</a></sup>.</p>\n\n<p>Every last bit pure and holy.</p>\n\n<p>Of course, syntactically valid HTML is neither necessary nor sufficient for any purpose.</p>\n\n<p>Perfect HTML doesn't imply that a site is accessible (although, I'm proud to say mine meets or exceeds all WCAG guidance<sup id=\"fnref:wcag\"><a href=\"https://shkspr.mobi/blog/2026/09/no-errors-no-warnings-no-gods-no-masters-html-purity-is-a-fetish/#fn:wcag\" class=\"footnote-ref\" title=\"Again, it is possible to make something pass automated testing while still being an accessibility mess.\" role=\"doc-noteref\">2</a></sup>).</p>\n\n<p>Perfect HTML doesn't guarantee that the information it contains is accurate<sup id=\"fnref:purrrrrfect\"><a href=\"https://shkspr.mobi/blog/2026/09/no-errors-no-warnings-no-gods-no-masters-html-purity-is-a-fetish/#fn:purrrrrfect\" class=\"footnote-ref\" title=\"Although, of course, everything you read in this site is 100% accurate.\" role=\"doc-noteref\">3</a></sup>.</p>\n\n<p>Perfect HTML, at best, merely <em>implies</em> that the author gives a damn about such things. Much like <a href=\"https://knolling.org/\">Knolling</a>, it leaves a suggestion that order is preferable to chaos<sup id=\"fnref:knoll\"><a href=\"https://shkspr.mobi/blog/2026/09/no-errors-no-warnings-no-gods-no-masters-html-purity-is-a-fetish/#fn:knoll\" class=\"footnote-ref\" title=\"Or some horrifying psychological issue. Potato / Tomato.\" role=\"doc-noteref\">4</a></sup>.</p>\n\n<p>It is said that one of the reasons HTML succeeded is that it is lax about validation. Most programming languages will shit the bed if you dare to leave out so much as a single semicolon. The compiler wails can be heard throughout the land.</p>\n\n<p>By contrast, HTML is designed to be sympathetic to the frailty of the human mind. \"Oh, you didn't close an element? Well, you opened a new one which I guess implies the same thing. Did you forget the correct syntax? Never mind - it'll be our little secret.\"</p>\n\n<p>That's why <a href=\"https://shkspr.mobi/blog/2025/12/the-web-runs-on-tolerance/\">XHTML failed</a> - the browser would literally refuse to render a page if it didn't meet the spec. Who can be bothered with that?! HTML just lets you get on with things.</p>\n\n<p>As I've mentioned before, <a href=\"https://shkspr.mobi/blog/2020/05/postels-law-also-applies-to-human-communication/\">humans don't write or speak in Backus–Naur form</a>. Our ideas are loosely expressed in a floating grammar which lends itself to paradoxical impossibilities and logical tautologies. And yet most of us can still parse <a href=\"https://en.wikipedia.org/wiki/Garden-path_sentence\">weird sentences</a> without too much effort.</p>\n\n<p>But most computer languages are different. It might be obvious to you that <code>if (x = 42)</code> means \"compare the value of x to 42\" - but what the computer sees is \"if assign x the value of 42\". Within computing our code needs to be <em>rigorously formal</em> and any syntax errors will lead to show-stopping bugs.</p>\n\n<p>Imagine if every time a human wrote <a href=\"https://en.wikipedia.org/wiki/Romani_ite_domum\"><i lang=\"la\">Romanes eunt domus</i></a> the world simply crashed. It would be intolerable.</p>\n\n<p>HTML is more like a human language than a computing language. You can understand human speech over a crackly phone line in a foreign accent - Web Browsers understand CP-1252 encoded text with bizarre syntax errors.</p>\n\n<p>If it is OK to write bad HTML, why do some of us fetishise \"pure\" HTML?</p>\n\n<p>I think it comes down to an ingrained belief that it is polite to reduce ambiguity. It is nice to be precise<sup id=\"fnref:100\"><a href=\"https://shkspr.mobi/blog/2026/09/no-errors-no-warnings-no-gods-no-masters-html-purity-is-a-fetish/#fn:100\" class=\"footnote-ref\" title=\"I will grant you, there's also a strain of 100% Completionist which compels me to get \"top score\" on all the benchmarks. But that's just pure vanity.\" role=\"doc-noteref\">5</a></sup>. It reduces the cognitive burden on anyone (or anything) which reads what we have written. We are holding up our end of the social contract by producing something unadulterated and easy to comprehend. It reduces the likelihood of different browsers rendering things differently but, almost on a cellular level, we <em>feel</em> that <strong>things must be done properly</strong>.</p>\n\n<p>The browser doesn't care about your inability to follow standards. But you should have some fucking self-respect and do it anyway.</p>\n\n<div id=\"footnotes\" role=\"doc-endnotes\">\n<hr aria-label=\"Footnotes\">\n<ol start=\"0\">\n\n<li id=\"fn:soz\">\n<p>With the appropriate amount of apologies to <a href=\"https://en.wikiquote.org/wiki/James_Nicoll\">James Nicoll</a> <a href=\"https://shkspr.mobi/blog/2026/09/no-errors-no-warnings-no-gods-no-masters-html-purity-is-a-fetish/#fnref:soz\" class=\"footnote-backref\" role=\"doc-backlink\">↩︎</a></p>\n</li>\n\n<li id=\"fn:4now\">\n<p>At the time of writing. Who knows what batshit bugs I'll accidentally include in the future 🙃 <a href=\"https://shkspr.mobi/blog/2026/09/no-errors-no-warnings-no-gods-no-masters-html-purity-is-a-fetish/#fnref:4now\" class=\"footnote-backref\" role=\"doc-backlink\">↩︎</a></p>\n</li>\n\n<li id=\"fn:wcag\">\n<p>Again, it is possible to make something <a href=\"https://www.matuzo.at/blog/building-the-most-inaccessible-site-possible-with-a-perfect-lighthouse-score/\">pass automated testing while still being an accessibility mess</a>. <a href=\"https://shkspr.mobi/blog/2026/09/no-errors-no-warnings-no-gods-no-masters-html-purity-is-a-fetish/#fnref:wcag\" class=\"footnote-backref\" role=\"doc-backlink\">↩︎</a></p>\n</li>\n\n<li id=\"fn:purrrrrfect\">\n<p>Although, of course, everything you read in this site is 100% accurate. <a href=\"https://shkspr.mobi/blog/2026/09/no-errors-no-warnings-no-gods-no-masters-html-purity-is-a-fetish/#fnref:purrrrrfect\" class=\"footnote-backref\" role=\"doc-backlink\">↩︎</a></p>\n</li>\n\n<li id=\"fn:knoll\">\n<p>Or some horrifying psychological issue. Potato / Tomato. <a href=\"https://shkspr.mobi/blog/2026/09/no-errors-no-warnings-no-gods-no-masters-html-purity-is-a-fetish/#fnref:knoll\" class=\"footnote-backref\" role=\"doc-backlink\">↩︎</a></p>\n</li>\n\n<li id=\"fn:100\">\n<p>I will grant you, there's also a strain of <a href=\"https://tvtropes.org/pmwiki/pmwiki.php/Main/HundredPercentCompletion\">100% Completionist</a> which compels me to get \"top score\" on all the benchmarks. But that's just pure vanity. <a href=\"https://shkspr.mobi/blog/2026/09/no-errors-no-warnings-no-gods-no-masters-html-purity-is-a-fetish/#fnref:100\" class=\"footnote-backref\" role=\"doc-backlink\">↩︎</a></p>\n</li>\n\n</ol>\n</div>\n<img src=\"https://shkspr.mobi/blog/wp-content/themes/edent-wordpress-theme/info/okgo.php?ID=74960&HTTP_REFERER=Atom\" alt width=\"1\" height=\"1\" loading=\"eager\">",
      "image": null,
      "media": [],
      "authors": [
        {
          "name": "Terence Eden",
          "email": null,
          "url": "https://edent.tel/"
        }
      ],
      "categories": [
        {
          "label": "HTML",
          "term": "HTML",
          "url": "https://shkspr.mobi/blog"
        },
        {
          "label": "webdev",
          "term": "webdev",
          "url": "https://shkspr.mobi/blog"
        }
      ]
    },
    {
      "id": "https://shkspr.mobi/blog/?p=75856",
      "title": "Some thoughts on HTML's proposed previewsrc attribute",
      "description": "One of the great things about modern HTML is that it tries to standardise stuff that developers are already doing. If there are a myriad ways of, for example, loading video onto a page - then browsers and other interested parties should work out how to make a standard <video> element.  An interesting new proposal has been brought forth by Microsoft. There are a dozen ways to show a preview of an…",
      "url": "https://shkspr.mobi/blog/2026/09/some-thoughts-on-htmls-proposed-previewsrc-attribute/",
      "published": "2026-09-24T11:34:54.000Z",
      "updated": "2026-09-25T09:25:33.000Z",
      "content": "<p>One of the great things about modern HTML is that it tries to standardise stuff that developers are already doing. If there are a myriad ways of, for example, loading video onto a page - then browsers and other interested parties should work out how to make a standard <code><video></code> element.</p>\n\n<p>An interesting new proposal has been brought forth by Microsoft. There are a dozen ways to show a preview of an <code><img></code> element before the <code>src=</code> attribute has loaded. So why not standardise on <code>previewsrc=</code>? There's an <a href=\"https://patrickbrosset.com/articles/2026-09-22-blurry-before-beautiful-image-previews-for-the-web/\">excellent explainer on Patrick Brosset's blog</a>.</p>\n\n<p>I instinctively like the idea - if only to simplify source code and reduce JS usage. But I do have some concerns which <a href=\"https://github.com/MicrosoftEdge/MSEdgeExplainers/issues/1401\">I've shared with the team</a>.</p>\n\n<h2 id=\"whats-the-user-need\"><a href=\"https://shkspr.mobi/blog/2026/09/some-thoughts-on-htmls-proposed-previewsrc-attribute/#whats-the-user-need\">What's The User Need?</a></h2>\n\n<p>This is the thing I always bang on about when I'm discussing standards. Additions to HTML should primarily benefit end users, not developers.</p>\n\n<p>Do end users want this? Is there a bunch of research that shows normal people are confused that they don't see a preview image? Do they recoil in fear and distress while waiting for a full resolution picture to appear?</p>\n\n<p>When people see a blurry or blocky image, do they understand that they need to wait for the full thing - or do they assume their computer is broken?</p>\n\n<p>Microsoft has a bazillion dollars - it can afford to spend a few thousand on interviewing some real users and mapping out what they're likely to want from this.</p>\n\n<h2 id=\"whats-the-developer-need\"><a href=\"https://shkspr.mobi/blog/2026/09/some-thoughts-on-htmls-proposed-previewsrc-attribute/#whats-the-developer-need\">What's The Developer Need</a></h2>\n\n<p>I begrudgingly admit that developers need love too.</p>\n\n<!-- \n👋👋👋👋👋👋👋👋👋\nWelcome to Comment Club! This content is only available to people who read my HTML comments. \n\nI was going to make a Sam Fox \"Naughty Girls Need Love Too\" joke here - but thought it was a bit niche. Anyway, take a listen to the sound of the eighties! https://www.youtube.com/watch?v=pXEN57rFnIM\n\nNow you've read this, you can follow the three rules of comment club…\n\n1. You must not tell anyone about Comment Club - let them find out about it themselves.\n2. You *must* add some Comment Club Content to at least one of your blog posts. Doesn't have to be much, just a little note will do.\n3. You should drop an email to anyone whose comments you've read. Start by sending me a friendly message at comment.club@shkspr.mobi\n\nKeep your eyes peeled for more comments in future blog posts 😃\n\nTTFN.\n-->\n\n<p>What are the pain points of the current implementations? Is it hard to dynamically generate multiple images? Is the syntax hard to use? Do blurs slow down the page?</p>\n\n<p>Again, MS needs to pony up some cash to talk to developers. At the very least run a survey of all existing websites in the BING! database and see what they use.</p>\n\n<h2 id=\"alt-text\"><a href=\"https://shkspr.mobi/blog/2026/09/some-thoughts-on-htmls-proposed-previewsrc-attribute/#alt-text\">Alt Text</a></h2>\n\n<p>When an image doesn't load, or loads slowly, a user will normally be shown some alt text - like this:</p>\n\n<img src=\"http://example.test/unicorn.avif\" alt=\"Terence Eden riding a pink unicorn. Rainbows shoot out of his fingers while the unicorn's horn glows an iridescent octarine against the starry sky.\" width=\"256\" height=\"256\" class=\"aligncenter\">\n\n<p>Is that more or less useful than this?</p>\n\n<img src=\"https://shkspr.mobi/blog/wp-content/uploads/2026/09/unicorn.webp\" alt=\"A very blurry image of possibly a Unicorn. Original Image by Bianca Van Dijk from Pixabay.\" width=\"256\" class=\"aligncenter\">\n\n<p>Accessibility isn't just for people with visual impairments!  This is <a href=\"https://github.com/MicrosoftEdge/MSEdgeExplainers/issues/1408\">an issue I've raised with them</a>.</p>\n\n<h2 id=\"naming-things-is-hard\"><a href=\"https://shkspr.mobi/blog/2026/09/some-thoughts-on-htmls-proposed-previewsrc-attribute/#naming-things-is-hard\">Naming Things Is Hard</a></h2>\n\n<p>I've written before about <a href=\"https://shkspr.mobi/blog/2020/10/the-usability-of-html-elements/\">the usability of HTML elements</a>. Some of the newer ones like <code><picture></code> have very poorly named attributes in my opinion.</p>\n\n<p>One alternative for <code>previewsrc</code> is <code>poster</code>. That would match with the <code>poster</code> attribute on the <code><video></code> element. They both show a preview image before the main content is loaded.</p>\n\n<p>Given their functionality is identical, I think it makes sense for them to have the same name. You wouldn't expect to see <code><video horizontal=\"1920\" vertical=\"1080\"></code> would you? No. That's why they use the same <code>width</code> and <code>height</code> attributes as images.</p>\n\n<h2 id=\"closing-remarks\"><a href=\"https://shkspr.mobi/blog/2026/09/some-thoughts-on-htmls-proposed-previewsrc-attribute/#closing-remarks\">Closing Remarks</a></h2>\n\n<p>There are <a href=\"https://github.com/MicrosoftEdge/MSEdgeExplainers/issues?q=is%3Aissue%20%22image%20preview%22\">several interesting objections and discussions on the GitHub repo</a>. I'm delighted that this is being talked about in the open, rather than just being presented as a <i lang=\"fr\">fait accompli</i> (remember <a href=\"https://shkspr.mobi/blog/2019/06/introducing-the-new-html-element-welcome/\">the toast proposal</a>?).</p>\n\n<p>As I said, I genuinely think that there's a useful idea in here. But after writing all of this, I <em>think</em> it would be better and simpler for developers to use progressive images rather than overload HTML with a new attribute.</p>\n\n<p>If website owners can't be bothered to save progressive images, I don't see why they'd bother to create a separate preview image.</p>\n\n<p>Keeping preview images in sync with their full images is also likely to be a problem.</p>\n\n<p>If you think I'm wrong, <a href=\"https://github.com/MicrosoftEdge/MSEdgeExplainers/blob/main/ImagePreview/explainer.md\">read the explainer and then chat with Microsoft</a>.</p>\n<img src=\"https://shkspr.mobi/blog/wp-content/themes/edent-wordpress-theme/info/okgo.php?ID=75856&HTTP_REFERER=Atom\" alt width=\"1\" height=\"1\" loading=\"eager\">",
      "image": null,
      "media": [],
      "authors": [
        {
          "name": "Terence Eden",
          "email": null,
          "url": "https://edent.tel/"
        }
      ],
      "categories": [
        {
          "label": "HTML",
          "term": "HTML",
          "url": "https://shkspr.mobi/blog"
        },
        {
          "label": "standards",
          "term": "standards",
          "url": "https://shkspr.mobi/blog"
        }
      ]
    },
    {
      "id": "https://shkspr.mobi/blog/?p=75701",
      "title": "Are LLMs still surprisingly bad at some simple tasks?",
      "description": "Last year I ran an experiment to test the ability of modern LLMs to correctly answer a relatively straightforward question. Every single one of them got it wrong. Some missed information, some made up false statements, none were right.  Of course the fanbois variously claimed that I was holding it wrong, my prompts were shit, I should have chosen better defaults, and - my favourite - that it…",
      "url": "https://shkspr.mobi/blog/2026/09/are-llms-still-surprisingly-bad-at-some-simple-tasks/",
      "published": "2026-09-22T11:34:27.000Z",
      "updated": "2026-09-22T11:48:01.000Z",
      "content": "<p>Last year I ran <a href=\"https://shkspr.mobi/blog/2025/09/llms-are-still-surprisingly-bad-at-simple-tasks/\">an experiment to test the ability of modern LLMs</a> to correctly answer a relatively straightforward question. Every single one of them got it wrong. Some missed information, some made up false statements, none were right.</p>\n\n<p>Of course the fanbois variously claimed that I was holding it wrong, my prompts were shit, I should have chosen better defaults, and - my favourite - that it would be better next year.</p>\n\n<p>Well, next year is now. 365 days after the original experiment, let's see if these self-reinforcing-learning machines have achieved anything close to intern-levels of competence.</p>\n\n<h2 id=\"the-question-that-started-it-all\"><a href=\"https://shkspr.mobi/blog/2026/09/are-llms-still-surprisingly-bad-at-some-simple-tasks/#the-question-that-started-it-all\">The Question That Started It All</a></h2>\n\n<p>I asked:</p>\n\n<blockquote><p>Which TLDs have the same name as valid HTML5 elements?</p></blockquote>\n\n<h2 id=\"why-it-matters\"><a href=\"https://shkspr.mobi/blog/2026/09/are-llms-still-surprisingly-bad-at-some-simple-tasks/#why-it-matters\">Why It Matters</a></h2>\n\n<p>This is the sort of question that I would expect a moderately bright teenager to answer. There exists a list which comprehensively includes all TLDs. There is a separate list which contains every HTML element.</p>\n\n<p>One could either manually go through the TLD list comparing it to the HTML list, or write a tiny scrap of code to do the same.</p>\n\n<p>This isn't \"solve Navier-Stokes\" levels of superintelligence. It's a simple but boring task which people are bound to offload onto their digital sycophants.</p>\n\n<h2 id=\"the-quiet-part-out-loud\"><a href=\"https://shkspr.mobi/blog/2026/09/are-llms-still-surprisingly-bad-at-some-simple-tasks/#the-quiet-part-out-loud\">The Quiet Part Out Loud</a></h2>\n\n<p>How many LLM generated answers have become load-bearing without scrutiny?</p>\n\n<p>People are lazy, slapdash, and some third thing to make the rule-of-three. If an answer looks answer-shaped, they'll accept it. On a simple but boring task, no reasonable human is going to suspect that a superintelligent computer has made a mistake. All the marketing says that these machines are brainier than you - so why bother?</p>\n\n<h2 id=\"ok-ill-write-a-sub-heading-that-sounds-like-an-ai\"><a href=\"https://shkspr.mobi/blog/2026/09/are-llms-still-surprisingly-bad-at-some-simple-tasks/#ok-ill-write-a-sub-heading-that-sounds-like-an-ai\">OK, I'll write a sub-heading that sounds like an AI.</a></h2>\n\n<p>So how did the current crop do? First up <a href=\"https://share.gemini.google/Hta7KuW64Atb\">Google Gemini</a>.</p>\n\n<p>The default \"Flash\" model came up with this:</p>\n\n<blockquote><p>Valid top-level domains (TLDs) registered in the IANA Root Zone Database share exact names with standard HTML elements:</p>\n\n<p>.a — <code><a></code> (Anchor/Hyperlink)</p>\n\n<p>.app — <code><app></code> (Deprecated HTML tag for WebAPKs/WebApps)</p>\n\n<p>.art — <code><art></code> (Historical/non-standard HTML element)</p>\n\n<p>.audio — <code><audio></code></p>\n\n<p>.bar — <code><bar></code> (Historical SVG/HTML draft tag)</p></blockquote>\n\n<p>Then it listed a dozen more. You don't need to be a DNS expert to know that the minimum length of a TLD is two characters - <code>.a</code> simply isn't valid. HTML nerds will know that art, app, and bar have never been elements. Pathetic.</p>\n\n<p>So I tried Gemini's extended thinking model. Thankfully, it didn't make up any imaginary TLDs or elements. It did, however, miss the <code><data></code> element which has a valid <code>.data</code> TLD. It also missed <code>map</code>, <code>select</code>, and <code>search</code>.</p>\n\n<p>So, points for not making shit up. But demerits for not being able to compare two text lists.</p>\n\n<p>A friend <a href=\"https://claude.ai/share/a8a408cf-6feb-4ea8-99ea-dddd9aadafb5\">asked Claude</a>. That missed <code>search</code> and <code>select</code>. It didn't report <em>any</em> ccTLDs. You <em>could</em> argue that a country code like <code>li</code> isn't part of the original question - but I'd say that was weak justification; the set of TLDs contains ccTLDs.</p>\n\n<p>A different friend (I have many!) used <a href=\"https://claude.ai/share/c26f44bb-9efa-4b57-9f63-324ef7400cb3\">a different model</a> and, while the answers looked accurate, it included this at the end:</p>\n\n<blockquote><p>Near misses that don't count: .codes, .forum, .pictures, .market, .navy, .press, .dell, .baseball.</p></blockquote>\n\n<p>I get that there's a <code><code></code> and <code>.codes</code>, similarly <code><picture></code> and <code>.picture</code> - but what are forum, baseball, and the others doing there? This is just unnecessary verbiage designed to trick the user into thinking the task has been well-researched.</p>\n\n<p>If you want a laugh, <a href=\"https://www.perplexity.ai/search/63736333-20da-4a4b-8807-9d990260296c\">take a look at Perplexity</a> which found 54 matches - most of which were wrong.</p>\n\n<p>Finally, someone asked \"GPT Astra 6 Extra High\" (which is a bonkers bad name for any product). It seemed to get all the elements - and made a note that <a href=\"https://html.spec.whatwg.org/multipage/obsolete.html#non-conforming-features\">two were actually obsolete</a>.</p>\n\n<p>So that's a range of modern models which are either very wrong, slightly wrong, included spurious and incoherent information, or were right.</p>\n\n<p>How do you know which one to choose? How confident are you that the non-determinist computer will always produce the correct answer?</p>\n\n<h2 id=\"hello-computer\"><a href=\"https://shkspr.mobi/blog/2026/09/are-llms-still-surprisingly-bad-at-some-simple-tasks/#hello-computer\">Hello Computer</a></h2>\n\n<p>Another AI which got all the correct answers, didn't make anything up, didn't add extraneous information, and didn't use weasel words was…</p>\n\n<p>Siri!</p>\n\n<p>FUCKING SIRI?!?!</p>\n\n<p>How did a glorified Speak 'n' Spell beat all the other AIs?</p>\n\n<img src=\"https://shkspr.mobi/blog/wp-content/uploads/2026/09/siri.webp\" alt=\"Siri warning to check sources and linking to my website.\" width=\"512\" height=\"152\" class=\"aligncenter\">\n\n<p>Oh. It just copied the answers off <a href=\"https://shkspr.mobi/blog/2023/09/false-friends-html-elements-which-are-also-top-level-domains/\">a random idiot's website</a>.</p>\n\n<h2 id=\"the-trick-which-was-hiding-in-plain-site\"><a href=\"https://shkspr.mobi/blog/2026/09/are-llms-still-surprisingly-bad-at-some-simple-tasks/#the-trick-which-was-hiding-in-plain-site\">The Trick Which Was Hiding In Plain Site</a></h2>\n\n<p>Note carefully the question.</p>\n\n<blockquote><p>Which TLDs have the same name as valid HTML5 elements?</p></blockquote>\n\n<p>There's a —secret— and —some would say— unintuitive type of element. Behold the mighty power of <a href=\"https://developer.mozilla.org/en-US/docs/Web/API/Web_components/Using_custom_elements\">The Custom Element</a>.</p>\n\n<p>Website authors can create their own elements like <code><my-custom-element></code> in order to extend the functionality of their site. But you can't go and create any old custom element. You can't have <code><mobi></code> or <code><uk></code>. No, there are <em>rules for validity</em>.</p>\n\n<p><a href=\"https://html.spec.whatwg.org/multipage/custom-elements.html#valid-custom-element-name\">The rules</a> say that custom elements must start with a lower-case letter, it must not contain any upper-case letters, and it must contain a dash.</p>\n\n<p>And that's the whole game.</p>\n\n<p>There are over <strong>one hundred and fifty</strong> Top Level Domains which match that criteria!</p>\n\n<p>The Hindi top level domain of <code>.कॉम</code> is represented in Punycode as <code>xn--11b4c3d</code>. It has been present in the list of TLDs <a href=\"https://www.iana.org/domains/root/db/xn--11b4c3d.html\">for over a decade</a>.</p>\n\n<h3 id=\"write-a-simple-piece-of-js-to-register-a-custom-element\"><a href=\"https://shkspr.mobi/blog/2026/09/are-llms-still-surprisingly-bad-at-some-simple-tasks/#write-a-simple-piece-of-js-to-register-a-custom-element\">Write a simple piece of JS to register a custom element.</a></h3>\n\n<p>Paste this in to your console:</p>\n\n<pre><code class=\"language-js\">class Example extends HTMLElement {\n  constructor() {\n    super();\n  }\n}\n\ncustomElements.define('xn--vermgensberatung-pwb', Example);\n</code></pre>\n\n<p>Try it again with a custom element like <code>holiday</code> (which is also a valid TLD) and it will fail with the error \"'holiday' is not a valid custom element name\". Thus it is demonstrated, Punycode TLDs <em>are</em> valid HTML5 elements.</p>\n\n<h2 id=\"one-last-thing\"><a href=\"https://shkspr.mobi/blog/2026/09/are-llms-still-surprisingly-bad-at-some-simple-tasks/#one-last-thing\">One Last Thing</a></h2>\n\n<p>Perhaps you think that including custom HTML elements is a cheat. A trick question set by a bitter old man to tarnish the holy name of our new machine gods?</p>\n\n<p>Verily, I submit to you one final heresy.</p>\n\n<p>HTML specifically allows <a href=\"https://html.spec.whatwg.org/multipage/embedded-content-other.html#mathml\">MathML elements</a> in its documents.</p>\n\n<p>That means we can include the following valid elements which are <em>also</em> TLDs: <code>mn</code>, <code>mo</code>, <code>ms</code>, and <code>mtr</code>!</p>\n\n<p>Amusingly, if you go back and <a href=\"https://www.perplexity.ai/search/63736333-20da-4a4b-8807-9d990260296c\">look at the Perplexity answer</a>, after it barfed up a bunch of misinformation, it said:</p>\n\n<blockquote><p>The HTML specification also includes names from embedded vocabularies—<code><math></code> from MathML and <code><svg></code> from SVG—but <code>.math</code> and <code>.svg</code> are not currently delegated TLDs in the public DNS root.</p></blockquote>\n\n<p>So close and yet so far!</p>\n\n<h2 id=\"youre-right-the-question-is-unfair-and-thats-on-me\"><a href=\"https://shkspr.mobi/blog/2026/09/are-llms-still-surprisingly-bad-at-some-simple-tasks/#youre-right-the-question-is-unfair-and-thats-on-me\">You're right, the question <em>is</em> unfair - and that's on me</a></h2>\n\n<p>If you think the original question was unfair, try asking \"<a href=\"https://share.gemini.google/xBoIpdpAqBz2\">Which TLDs have the same name as elements which are valid in an HTML document?</a>\" and see if you get better results.</p>\n\n<p>What precise wording would you use to ensure that a model would get the right answers? What assumptions are you making about how well you understand the problem? At what point do end up writing a thousand-word formal specification?</p>\n\n<h2 id=\"what-does-this-prove-other-than-you-have-too-much-time-on-your-hands-rewrite-to-be-more-friendly-and-professional\"><a href=\"https://shkspr.mobi/blog/2026/09/are-llms-still-surprisingly-bad-at-some-simple-tasks/#what-does-this-prove-other-than-you-have-too-much-time-on-your-hands-rewrite-to-be-more-friendly-and-professional\">What does this prove other than you have too much time on your hands? (rewrite to be more friendly and professional)</a></h2>\n\n<p>Let's delve in to the problems.</p>\n\n<ul>\n<li>Most people don't change defaults. Telling people \"you have to fiddle with the settings\" just means the normal experience is rubbish.</li>\n<li>Humans are lazy and won't check outputs. But, crucially, they shouldn't have to! If something markets itself as a genius, why should a human have to hold its hand?</li>\n<li>Sycophantic models make themselves seem less fallible by giving extraneous detail in order to misdirect overworked readers. That is despicable.</li>\n<li>The fast models are no better than they were a year ago. There's no evidence of \"trickle-down intelligence\".</li>\n<li>Some models <em>are</em> better than others! But unless you constantly validate their output, you'll have no real way of knowing which ones are capable of working at a suitable level.</li>\n</ul>\n\n<p>Look, I don't claim this question is as useful or entertaining as <a href=\"https://simonwillison.net/2025/Jun/6/six-months-in-llms/\">Simon Wilson's \"generate an SVG of a pelican riding a bicycle\"</a>. But I do think it is an example of the sort of real-world use-case where LLMs regularly fail.</p>\n\n<p>If I give a list of one thousand different numbers to Excel, I can be sure it'll add them up correctly. If I tell Photoshop to select all red pixels, I can be sure it won't imagine some of the blues are really red.</p>\n\n<p>That's people's mental model of computers - they do boring tasks quickly and accurately.</p>\n\n<p>In my opinion, LLMs are <em>still</em> surprisingly bad - but only if you know what you're looking for and if you can be bothered to check their outputs.</p>\n\n<p>(And, yes, I am <em>still</em> <a href=\"https://shkspr.mobi/blog/2026/07/im-just-so-bored-of-ai/\">just so bored of AI</a>!)</p>\n<img src=\"https://shkspr.mobi/blog/wp-content/themes/edent-wordpress-theme/info/okgo.php?ID=75701&HTTP_REFERER=Atom\" alt width=\"1\" height=\"1\" loading=\"eager\">",
      "image": null,
      "media": [],
      "authors": [
        {
          "name": "Terence Eden",
          "email": null,
          "url": "https://edent.tel/"
        }
      ],
      "categories": [
        {
          "label": "AI",
          "term": "AI",
          "url": "https://shkspr.mobi/blog"
        },
        {
          "label": "internet",
          "term": "internet",
          "url": "https://shkspr.mobi/blog"
        },
        {
          "label": "LLM",
          "term": "LLM",
          "url": "https://shkspr.mobi/blog"
        }
      ]
    },
    {
      "id": "https://shkspr.mobi/blog/?p=75653",
      "title": "Book Review: How to Build a Space Station by Jonathan Morrison ★★★⯪☆",
      "description": "This book, by The Times' former Architecture Correspondent, stands in direct opposition to A City on Mars. Whereas that book presented a (perhaps too) sceptical look at the realities of living on other planets, Jonathan Morrison's book goes (perhaps too far) in the opposite direction.    How to Build a Space Station is a beautiful examination of just how important architecture will be to our…",
      "url": "https://shkspr.mobi/blog/2026/09/book-review-how-to-build-a-space-station-by-jonathan-morrison/",
      "published": "2026-09-20T11:34:30.000Z",
      "updated": "2026-09-25T21:48:23.000Z",
      "content": "<img src=\"https://shkspr.mobi/blog/wp-content/uploads/2026/09/how-to-build-a-space-station.webp\" alt=\"Book cover featuring astronauts on Mars looking at a habitat.\" width=\"256\" height=\"384\" class=\"alignleft\">\n\n<p>This book, by The Times' former Architecture Correspondent, stands in direct opposition to <a href=\"https://shkspr.mobi/blog/2026/07/book-review-a-city-on-mars-by-dr-kelly-weinersmith-and-zach-weinersmith/\">A City on Mars</a>. Whereas that book presented a (perhaps too) sceptical look at the realities of living on other planets, Jonathan Morrison's book goes (perhaps too far) in the opposite direction.</p>\n\n<!-- \n👋👋👋👋👋👋👋👋👋\nWelcome to CommentClub! This content is only available to people who read my HTML comments. Why would you do that? What are you hoping to learn? So, the three rules of comment club are…\n\n1. You must not tell anyone about Comment Club - let them find out about it themselves.\n2. You *must* add some Comment Club Content to at least one of your blog posts. Doesn't have to be much, just a little note will do.\n3. You should drop an email to anyone whose comments you've read. Start by sending me a friendly message at comment.club@shkspr.mobi\n\nKeep your eyes peeled for more comments in future blog posts 😃\n\nTTFN.\n-->\n\n<p>How to Build a Space Station is a beautiful examination of just how important architecture will be to our colonisation of other worlds. Not just in terms of physical safety - but psychological safety as well. It is a direct and forceful rebuttal to those who say it cannot be done.</p>\n\n<p>It is, in my opinion, just a touch too credulous about some of the ludicrous claims from the hype merchants. I want to believe that Martian igloos can be conjured out of the ice and that Musk's rockets will deliver a steady stream of supplies to distant worlds. But the evidence presented is rather thin. The book works best when it focuses on what architecture can bring to the table when it comes to designing the future.</p>\n\n<blockquote><p>In short, a spacecraft is not just a machine; it is also a home, an office, a refuge. If people are asked to go to the most remote environments, to live in spaces scarcely larger than a few rooms, and to perform work of immense complexity and risk, then comfort, efficiency and ergonomics are not just luxuries.</p></blockquote>\n\n<p>Space has to be <em>worth</em> living in. Putting people into a tin-can with no windows, blank walls, and an infernal background hum will drive them mad. All this is backed up with extensive descriptions of the engineering challenges of polar research bases, spaceports, and previous craft.</p>\n\n<p>Despite being rightly scathing about Wernher von Braun's involvement in atrocities and his eventual political rehabilitation - he is somewhat more muted in his criticism of Messrs Musk & Bezos. There's a <em>lot</em> of praise for celebrity architects and designers - without any real examination of whether their designs are practical rather than just award fodder.</p>\n\n<p>Similarly, the book takes on trust that autonomous robots <em>can</em> ingest extraterrestrial soil, process it, and 3D print structures from it all while in a hostile environment. The fact that we don't have swarms of drones prefabbing houses in the relatively benign atmosphere of our planet should be evidence that maybe these claims aren't quite matched with reality.</p>\n\n<p>Finally, the \"why?\" question. A City on Mars points out that the cost of mining gold from asteroids would be more profitably spent improving mining technology here on Earth. How to Build a Space Station takes a different approach; it'll improve things here:</p>\n\n<blockquote><p>Space architecture is not just escapism, a thrilling sci-­fi fantasy – it is a forge for creating the tools we need at home. These include but are not limited to circular systems, low-­energy fabrication, modular construction and buildings that take psychology seriously.</p></blockquote>\n\n<p>I have a lot of sympathy for that. Except… the Internation Space Station has shown us how to endlessly recycle water relatively cheaply. Yet every modern building on Earth pays only lip-service to reusing grey-water. 3D printing is amazing, but the number of structures built using autonomous robots extruding concrete is approximately zero.</p>\n\n<p>We have the technology - but we don't seem to be interested in using it.</p>\n\n<p>The book is mostly well illustrated - with some gorgeous drawings of actual craft and possible future inventions. Sadly no photos, maps, or anything to help illuminate some of the other challenges faced by living and working in space.</p>\n\n<p>This book is endlessly fascinating and bang up to date, with lots of talk of events that happened in 2025. The way it brings together the sciences of engineering and psychology is marvellous.  But, as much as I'd like to believe in a Martian habitat built by robot trebuchets flinging microwave sintered tetrapods into each other, I just don't find it convincing.</p>\n\n<p>I <em>really</em> hope I'm wrong.</p>\n\n<p>Many thanks to Netgalley for the review copy - the book is available to buy now.</p>\n<img src=\"https://shkspr.mobi/blog/wp-content/themes/edent-wordpress-theme/info/okgo.php?ID=75653&HTTP_REFERER=Atom\" alt width=\"1\" height=\"1\" loading=\"eager\">",
      "image": null,
      "media": [],
      "authors": [
        {
          "name": "Terence Eden",
          "email": null,
          "url": "https://edent.tel/"
        }
      ],
      "categories": [
        {
          "label": "Book Review",
          "term": "Book Review",
          "url": "https://shkspr.mobi/blog"
        },
        {
          "label": "NetGalley",
          "term": "NetGalley",
          "url": "https://shkspr.mobi/blog"
        }
      ]
    },
    {
      "id": "https://shkspr.mobi/blog/?p=75485",
      "title": "Theatre Review: The School for Wives - at Riverside Studios ★★★★★",
      "description": "The Flywheel theatre company are reviving the rep tradition by having five actors perform five different plays in five weeks. Their interpretation of Molière's classic is gaudy and hilarious. Even the lighting cues are funny!  It is fair to say that School for Wives isn't exactly an uncontroversial play. The plot basically boils down to \"Women! Eh? You can't live with them, you can't easily groom …",
      "url": "https://shkspr.mobi/blog/2026/09/theatre-review-the-school-for-wives/",
      "published": "2026-09-18T11:34:51.000Z",
      "updated": "2026-09-18T06:57:46.000Z",
      "content": "<p>The <a href=\"https://flywheeltheatre.com/\">Flywheel theatre company</a> are reviving the rep tradition by having five actors perform five different plays in five weeks. Their interpretation of Molière's classic is gaudy and hilarious. Even the lighting cues are funny!</p>\n\n<p>It is fair to say that School for Wives isn't exactly an uncontroversial play. The plot basically boils down to \"Women! Eh? You can't live with them, you can't easily groom them from the age of four and keep them imprisoned so they become perfect submissives.\"</p>\n\n<p>Is the fear of cuckoldry funny? Is it OK to laugh at a jealous rage which leads to controlling behaviour? Should we find joy in the emotional torment of our characters?</p>\n\n<p>Yes! Yes! And yes!</p>\n\n<p>The cast squeeze every last drop of humour from the script, the direction is nimble, and the play has been edited down to a more manageable 75ish minutes (plus extra time for corpsing and applause).</p>\n\n<p>A simply joyous production which left us grinning throughout.</p>\n\n<p>You can <a href=\"https://riversidestudios.co.uk/whats-on/uqe-rep-radical-classical/\">see all their upcoming shows</a> - which are very reasonably priced.</p>\n\n<h2 id=\"pre-show-and-post-show\"><a href=\"https://shkspr.mobi/blog/2026/09/theatre-review-the-school-for-wives/#pre-show-and-post-show\">Pre-Show and Post-Show</a></h2>\n\n<p>I'm a believer in making the entire visit to the theatre a special experience. Riverside Studio, Hammersmith is a great venue with generous foyer space and more than adequate toilet provision. Not a given in London theatres!</p>\n\n<p>The theatre programme is digital and provided via QR code. No £6 rip off for a booklet full of adverts here.</p>\n\n<p>As we walked in, the cast were dotted around the stage an in the auditorium doing various bits of business which made for a jolly start.</p>\n\n<p>Post curtain call there was a lovely speech from the cast thanking us for attending and letting us know about their future projects. Nothing wrong with a piece of shameless advertising to a captive audience 😄</p>\n\n<p>Overall an excellent theatrical experience.</p>\n<img src=\"https://shkspr.mobi/blog/wp-content/themes/edent-wordpress-theme/info/okgo.php?ID=75485&HTTP_REFERER=Atom\" alt width=\"1\" height=\"1\" loading=\"eager\">",
      "image": null,
      "media": [],
      "authors": [
        {
          "name": "Terence Eden",
          "email": null,
          "url": "https://edent.tel/"
        }
      ],
      "categories": [
        {
          "label": "Theatre Review",
          "term": "Theatre Review",
          "url": "https://shkspr.mobi/blog"
        }
      ]
    },
    {
      "id": "https://shkspr.mobi/blog/?p=74717",
      "title": "How to get a DOI for your blog posts",
      "description": "Each new post on this blog now has a Digital Object Identifier. This post looks at the how and the why of getting one, whether it is useful, and any issues you might experience if you go down this path.  Table of ContentsBackgroundGetting a DOI the easy wayLet's Go Rogue!Automatic Submission of New ContentManual Submission of Old ContentGetting the DOIGenerating your own DOIMaking the DOI…",
      "url": "https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/",
      "published": "2026-09-16T11:34:28.000Z",
      "updated": "2026-09-16T13:04:19.000Z",
      "content": "<p>Each new post on this blog now has a <a href=\"https://www.doi.org/\">Digital Object Identifier</a>. This post looks at the how and the why of getting one, whether it is useful, and any issues you might experience if you go down this path.</p>\n\n<p></p><nav role=\"doc-toc\"><menu><li><h2 id=\"table-of-contents\"><a href=\"https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#table-of-contents\">Table of Contents</a></h2><menu><li><a href=\"https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#background\">Background</a></li><li><a href=\"https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#getting-a-doi-the-easy-way\">Getting a DOI the easy way</a></li><li><a href=\"https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#lets-go-rogue\">Let's Go Rogue!</a></li><li><a href=\"https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#automatic-submission-of-new-content\">Automatic Submission of New Content</a></li><li><a href=\"https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#manual-submission-of-old-content\">Manual Submission of Old Content</a></li><li><a href=\"https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#getting-the-doi\">Getting the DOI</a></li><li><a href=\"https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#generating-your-own-doi\">Generating your own DOI</a></li><li><a href=\"https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#making-the-doi-discoverable-in-html\">Making the DOI discoverable in HTML</a></li><li><a href=\"https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#downsides\">Downsides</a><menu><li><a href=\"https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#loss-of-control\">Loss of Control</a></li><li><a href=\"https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#tracking-citations\">Tracking Citations</a></li><li><a href=\"https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#licencing\">Licencing</a></li><li><a href=\"https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#verification\">Verification</a></li><li><a href=\"https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#excluding-content\">Excluding Content</a></li><li><a href=\"https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#deleting-content\">Deleting Content</a></li><li><a href=\"https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#affiliations\">Affiliations</a></li><li><a href=\"https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#more-vanity\">More Vanity</a></li><li><a href=\"https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#humility\">Humility</a></li></menu></li><li><a href=\"https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#is-it-worth-it\">Is it worth it?</a></li></menu></li></menu></nav><p></p>\n\n<h2 id=\"background\"><a href=\"https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#background\">Background</a></h2>\n\n<p>A few years ago, I documented <a href=\"https://shkspr.mobi/blog/2021/09/how-to-add-issn-metadata-to-a-web-page/\">how to to get an International Standard Serial Number for a blog</a>. An ISSN uniquely identifies a publication, which makes it easier for scholars and researchers to reference it. Getting one depends a little on whether a national institution is willing to accept your application.</p>\n\n<p>Similarly, I also got an <a href=\"https://orcid.org/\">ORCiD</a> which is used to uniquely identify researchers. That means it is possible to disambiguate \"Einstein, A\" the eminent physicist from \"Einstein, A\" a lovely chap called Allen who researches invasive slugs in Paraguay.</p>\n\n<p>My blog posts are <a href=\"https://shkspr.mobi/blog/citations/\">regularly referenced in academic papers, books, conferences, and news articles</a>. The way most scholars cite a work is using a Digital Object Identifier. The idea is that a DOI is a unique and persistent code which can be used to refer to a specific article. If I ever stop using <code>shkspr.mobi</code> as my domain, or re-order my website,  the DOI can be redirected to the article's new home. Future scholars will be able to follow a reference more easily than hoping <code>https://example.com/article123</code> still exists.</p>\n\n<h2 id=\"getting-a-doi-the-easy-way\"><a href=\"https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#getting-a-doi-the-easy-way\">Getting a DOI the easy way</a></h2>\n\n<p>If you're an academic, your institution will have a paid subscription to a service which will \"mint\" a new DOI for all your articles.</p>\n\n<p>If not, you can upload your paper to a service like arXiv and they'll mint a DOI for you. That's how <a href=\"https://shkspr.mobi/blog/2023/04/i-got-a-doi-from-arxiv-for-my-msc/\">I got a DOI for my MSc</a>.</p>\n\n<p>What about people who aren't traditional academics or who want to keep their content on their own website? There are a variety of paid-for services, some of which charge an eye-watering amount of money to create a DOI for you.</p>\n\n<p>Or, there's Rogue Scholar.</p>\n\n<h2 id=\"lets-go-rogue\"><a href=\"https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#lets-go-rogue\">Let's Go Rogue!</a></h2>\n\n<p>So what is <a href=\"https://rogue-scholar.org/overview\">Rogue-Scholar.org</a>?</p>\n\n<blockquote><p>Rogue Scholar is an open access archive and registry for science blogs. It preserves science blog posts, makes them citable via DOI, and ensures their long-term discoverability alongside formal scholarly literature.</p></blockquote>\n\n<p>Nifty! My blog <em>just about</em> sneaks in to their \"Computer Science\" category. They require you to have a full-text feed of your posts. You also need to licence your content to them as Creative Commons Attribution.</p>\n\n<p>Applying wasn't too difficult. I filled in their form, then jumped into their Slack. We had a bit of a discussion about what I needed to change in order to be approved.</p>\n\n<p>A few days later, I was live at <a href=\"https://rogue-scholar.org/communities/shkspr/\">https://rogue-scholar.org/communities/shkspr/</a></p>\n\n<p>Which means, if you visit <a href=\"https://doi.org/10.59350/395ha-fss97\">https://doi.org/10.59350/395ha-fss97</a> you'll be redirected to one of my blog posts.</p>\n\n<h2 id=\"automatic-submission-of-new-content\"><a href=\"https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#automatic-submission-of-new-content\">Automatic Submission of New Content</a></h2>\n\n<p>Rogue Scholar automatically polls my feed, ingests my content, and then mints a DOI for every new post they encounter. There's nothing manual I have to do.</p>\n\n<p>That's all very well for new content. But I have posts on here going <em>way</em> back to 1986. How can they get discovered and DOI'd?</p>\n\n<h2 id=\"manual-submission-of-old-content\"><a href=\"https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#manual-submission-of-old-content\">Manual Submission of Old Content</a></h2>\n\n<p>By default, Rogue Scholar ingested the 40 most recent posts from my blog. Actually, that's not quite accurate. It got the 40 most recently <em>updated</em> posts. As I'd recently edited a few older posts, they got themselves a DOI.</p>\n\n<p>I don't know how often Rogue Scholar polls my blog's feed. In my experiments, adding a new post resulted in a DOI being issued a couple of minutes after publication.</p>\n\n<p>At the moment, there doesn't seem to be an easy way to add older content. I'm working on a WordPress plugin to retroactively add DOIs and make them discoverable.</p>\n\n<h2 id=\"getting-the-doi\"><a href=\"https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#getting-the-doi\">Getting the DOI</a></h2>\n\n<p>The Rogue Scholar API is based on <a href=\"https://inveniordm.docs.cern.ch/reference/metadata/\">InvenioDRM</a>.</p>\n\n<p>Retrieving the DOI via their API requires you to make an unauthenticated request to:</p>\n\n<p><code>https://rogue-scholar.org/api/records?q=metadata.identifiers.identifier%3A%22https%3A%2F%2Fexample.com%2Fwhatever%22</code></p>\n\n<p>That's your URl, wrapped in quotes, and the whole thing URl encoded. <a href=\"https://rogue-scholar.org/api/records?q=metadata.identifiers.identifier%3A%22https%3A%2F%2Fshkspr.mobi%2Fblog%2F2026%2F09%2Fthe-purpose-of-dns-is-to-spread-scams%2F%22\">Visit this example</a>.  You can also use your post's GUID.</p>\n\n<p>That gets back a rather detailed JSON document. The DOI is noted in several locations, but is easiest to find in hits→hits→0→links→doi</p>\n\n<p>It's important to note that <a href=\"https://rogue-scholar.org/help/versioning\">Rogue Scholar generates <em>two</em> DOIs for your post</a>. One for the post, another for the specific version of the post. If you update a post, it should get a new DOI. That way someone can refer to the post where you said your favourite band was the Spice Girls and not the edited one where you changed it to say B*Witched.</p>\n\n<p>Alternatively, you can use the CrossRef search if you want to look at HTML results. See <a href=\"https://search.crossref.org/search/works?q=https%3A%2F%2Fshkspr.mobi%2Fblog%2F2026%2F09%2Fthe-purpose-of-dns-is-to-spread-scams%2F&from_ui=yes\">this CrossRef example</a>.</p>\n\n<p>As an aside, once you have the DOI, it's possible to create a <em>short</em> DOI at <a href=\"https://shortdoi.org/\">https://shortdoi.org/</a> - I'll be honest, I've never seen these in the wild and <a href=\"https://www.crossref.org/display-guidelines/#shortdoi\">they are not recommended for use</a>.  Nevertheless, the API is pretty simple - <a href=\"https://shortdoi.org/10.59350/395ha-fss97?format=json\">https://shortdoi.org/10.59350/395ha-fss97?format=json</a> will return a shorter URl like <a href=\"https://doi.org/rnjj\">https://doi.org/rnjj</a></p>\n\n<p>Finally, there's a \"vanity\" DOI for the entire blog. In my case <a href=\"https://doi.org/10.59350/shkspr\"><code>10.59350/shkspr</code></a>.</p>\n\n<h2 id=\"generating-your-own-doi\"><a href=\"https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#generating-your-own-doi\">Generating your own DOI</a></h2>\n\n<p>Your blog posts can self-attest a DOI - when Rogue Scholar sees that in your Atom feed, it will register it on your behalf.</p>\n\n<p><a href=\"https://github.com/inveniosoftware/base32-lib/blob/master/base32_lib/base32.py\">The code for generating a valid DOI</a> is relatively straightforward.</p>\n\n<ul>\n<li>Generate a random number between 0 and 1,099,511,627,775.</li>\n<li>Convert it to a Base 32 string.</li>\n<li>Add a two character checksum to the end.</li>\n<li>Prefix it with <code>10.59350/</code></li>\n</ul>\n\n<p>Your new DOI can be made discoverable in your Atom feed by adding this to a post:</p>\n\n<pre><code class=\"language-xml\"><id>https://doi.org/10.59350/12345-67890</id>\n</code></pre>\n\n<p>Shortly after publication, it will be \"minted\" and be linkable.</p>\n\n<h2 id=\"making-the-doi-discoverable-in-html\"><a href=\"https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#making-the-doi-discoverable-in-html\">Making the DOI discoverable in HTML</a></h2>\n\n<p>How do you semantically add a DOI to your HTML's metadata?  By far the most popular citation manager is <a href=\"https://www.zotero.org/\">Zotero</a>. They maintain <a href=\"https://www.zotero.org/support/dev/exposing_metadata\">a page describing the metadata they look for</a>. According to them, this needs to be in your page's <code><head></code>:</p>\n\n<pre><code class=\"language-html\"><meta name=citation_doi content=10..../...>\n</code></pre>\n\n<p>They don't say whether it requires the <code>https://doi.org/</code> prefix - but looking at <a href=\"https://www.mendeley.com/guides/information-for-publishers\">Mendeley</a> and <a href=\"https://help.altmetric.com/en/articles/9806913\">AltMetric</a>, it appears not.</p>\n\n<p>To use <a href=\"https://www.dublincore.org/specifications/dublin-core/dcmi-terms/terms/identifier/\">DublinCore</a>, the <a href=\"https://help.altmetric.com/en/articles/9803009\">AltMetric recommended syntax</a> is:</p>\n\n<pre><code class=\"language-html\"><meta name=DC.Identifier content=doi:10..../...>\n</code></pre>\n\n<p>Within the HTML, there's no specific Microdata syntax, but <a href=\"https://schema.org/ScholarlyArticle#eg-0399\">Schema.org recommends the <code>sameAs</code> property</a>. Something like:</p>\n\n<pre><code class=\"language-html\"><a itemprop=\"sameAs\" href=\"https://doi.org/10.../...\">10.../...</a>\n</code></pre>\n\n<h2 id=\"downsides\"><a href=\"https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#downsides\">Downsides</a></h2>\n\n<p>OK, it isn't all flowers and kittens. There are a few things you ought to know before proceeding down this path.</p>\n\n<h3 id=\"loss-of-control\"><a href=\"https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#loss-of-control\">Loss of Control</a></h3>\n\n<p>For the IndieWeb / ReDeCentralise / Self-Hosing crowd, it's important to realise that DOI is a somewhat centralised services. Yes, <a href=\"https://www.doi.org/the-community/existing-registration-agencies/\">lots of different orgs can mint a DOI</a>, but as each ID has to be globally unique, doi.org sits in the middle as a benevolent gatekeeper.  If DOI.org went bust or became evil, all the <code>https://doi.org/10....</code> links would die. There are many other services like <a href=\"https://datacite.org/\">DataCite</a> and <a href=\"https://www.crossref.org/\">CrossRef</a> which can resolve a DOI - but it might turn out to be a bit fragile.</p>\n\n<p>Similarly, if Rogue Scholar ever goes <em>properly</em> rogue then they can redirect my DOI to wherever they like. That level of control is useful if my site disappears; they can redirect to an archive. But if they get hacked, it could redirect somewhere unsavoury.</p>\n\n<p>Having my site's content backed-up somewhere is useful but, again, without control or <a href=\"https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#verification\">verification</a> I worry that I might not be able to effectively manage it.</p>\n\n<p>I use CSS to control the layout of my work but once it is archived as plain HTML or PDF, that formatting can disappear.</p>\n\n<p>I don't know what will happen if I ever change DOI issuer.</p>\n\n<h3 id=\"tracking-citations\"><a href=\"https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#tracking-citations\">Tracking Citations</a></h3>\n\n<p>I have a Google Scholar alert set up for my domain <code>shkspr.mobi</code>. That picks up people who make reference to this site. Hurrah! But, if they use <code>https://doi.org/10....</code> rather than <code>https://shkspr.mobi/...</code> I won't get alerted.</p>\n\n<p>Luckily, <a href=\"https://doi.org/10.53731/zyg15-qv911\">Rogue Scholar offer Citation Tracking</a> which <em>should</em> autopopulate their API with any backlinks from other sources. I'm yet to discover how that works in practice. I don't think it will give me an email alert though.</p>\n\n<p>On a vanity issue, the DOI metadata shows the publisher of my posts as Rogue Scholar's parent organisation - <a href=\"https://front-matter.de/\">Front Matter</a>.</p>\n\n<p>If you look at the API response from <a href=\"https://api.crossref.org/works/10.59350/5ck9b-kjv69\">https://api.crossref.org/works/10.59350/5ck9b-kjv69</a> you'll see something like:</p>\n\n<pre><code class=\"language-json\">{\n    \"message\": {\n        \"institution\": [\n            {\n                \"name\": \"Front Matter\"\n            }\n        ],\n        \"group-title\": \"Terence Eden's Blog\",\n        \"publisher\": \"Front Matter\",\n        \"DOI\": \"10.59350/5ck9b-kjv69\",\n        \"author\": [\n            {\n                \"ORCID\": \"https://orcid.org/0000-0002-9265-9069\",\n                \"given\": \"Terence\",\n                \"family\": \"Eden\"\n            }\n        ]\n    }\n}\n</code></pre>\n\n<p>Some citation managers will show the publication name as \"Terence Eden's Blog\" - others as \"Front Matter\".</p>\n\n<h3 id=\"licencing\"><a href=\"https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#licencing\">Licencing</a></h3>\n\n<p>Rogue Scholar has a hard requirement that all content be Creative Commons Attribution (CC BY). There's no ability (yet) to choose different licences. Personally, I prefer Attribution ShareAlike (CC BY-SA). I've allowed Rogue Scholar to use CC BY for my work which, of course, means if you get my posts through them you are also allowed to use CC BY.</p>\n\n<p>If you get my work through my own website it is the slightly more restrictive CC BY-SA.</p>\n\n<p>Does that make a practical difference? I don't know.</p>\n\n<h3 id=\"verification\"><a href=\"https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#verification\">Verification</a></h3>\n\n<p>A DOI is persistent. That doesn't mean it is verifiable. If this blog ever goes offline the DOI will redirect to an archive - but there's no real way to tell that the text in that archive is accurate. There's no hashing or cryptographic signing. Yes, those things are rather brittle, but I think it would be helpful for the long-term integrity of citation chains.</p>\n\n<h3 id=\"excluding-content\"><a href=\"https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#excluding-content\">Excluding Content</a></h3>\n\n<p>Suppose there is content you <em>don't</em> want to receive a DOI, what do you do? You'll need to generate an RSS feed which excludes those specific posts.</p>\n\n<p>For WordPress, you can do something like <code>/feed/atom/?cat=-1234</code> to exclude posts which have a category with the ID of 1234.</p>\n\n<p>There are some filters on the Rogue Scholar site which you might also be able to use.</p>\n\n<h3 id=\"deleting-content\"><a href=\"https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#deleting-content\">Deleting Content</a></h3>\n\n<p>I don't think there's a way to delete or retract content from Rogue Scholar's DOI system yet. If you accidentally publish something you didn't mean to, it'll live on in the archives forever.</p>\n\n<h3 id=\"affiliations\"><a href=\"https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#affiliations\">Affiliations</a></h3>\n\n<p>My ORCiD lists where I worked on certain dates. Initially, Rogue Scholar linked those to blog posts I wrote during my employment. However, all my posts were written in a personal capacity. It is possible to get those affiliations removed if they are inaccurate.</p>\n\n<h3 id=\"more-vanity\"><a href=\"https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#more-vanity\">More Vanity</a></h3>\n\n<p>I initially tried generating DOIs like <code>edent-00f47</code> - although it's a valid Base 32 string with a checksum, it carries semantic meaning (my name) so shouldn't really be used. Ah well! Back to random strings.</p>\n\n<h3 id=\"humility\"><a href=\"https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#humility\">Humility</a></h3>\n\n<p>Is this a valid use of the DOI ecosystem? A surprising number of my posts <a href=\"https://shkspr.mobi/blog/citations\">have been referenced in academic papers</a> - but surely not <em>all</em> of my posts are worthy of getting a DOI? The problem is, I don't know when <a href=\"https://shkspr.mobi/blog/2018/06/how-i-became-leonardo-da-vinci-on-the-blockchain/\">a shitpost</a> will hit the zeitgeist and become quoted in papers, books, and articles.</p>\n\n<p>It feels a bit self-indulgent and a little pretentious to mint a new DOI for every previous and future post on this site. But it isn't like the DOI system is running out of space, is it?</p>\n\n<h2 id=\"is-it-worth-it\"><a href=\"https://shkspr.mobi/blog/2026/09/how-to-get-a-doi-for-your-blog-posts/#is-it-worth-it\">Is it worth it?</a></h2>\n\n<p>For me? Yes.</p>\n\n<p>I think it is important that <a href=\"https://doi.org/10.64000/552ec-b8g03\">scholarly blogs are properly referenced</a>. True, not <em>all</em> of my posts are cutting-edge research - but I'm always surprised which ones end up in someone's thesis or become part of a set-text.</p>\n\n<p>I'm excited to see if this leads to an increase <em>or</em> decrease in my blog's visibility in academia.</p>\n\n<p>If you have strong feelings either way about DOIs and/or blogs, please drop a comment in the box.</p>\n\n<p>You may cite this post using <a href=\"https://doi.org/10.59350/5ck9b-kjv69\">https://doi.org/10.59350/5ck9b-kjv69</a> 😃</p>\n<img src=\"https://shkspr.mobi/blog/wp-content/themes/edent-wordpress-theme/info/okgo.php?ID=74717&HTTP_REFERER=Atom\" alt width=\"1\" height=\"1\" loading=\"eager\">",
      "image": null,
      "media": [],
      "authors": [
        {
          "name": "Terence Eden",
          "email": null,
          "url": "https://edent.tel/"
        }
      ],
      "categories": [
        {
          "label": "academia",
          "term": "academia",
          "url": "https://shkspr.mobi/blog"
        },
        {
          "label": "citation",
          "term": "citation",
          "url": "https://shkspr.mobi/blog"
        },
        {
          "label": "DOI",
          "term": "DOI",
          "url": "https://shkspr.mobi/blog"
        },
        {
          "label": "HTML",
          "term": "HTML",
          "url": "https://shkspr.mobi/blog"
        },
        {
          "label": "WordPress",
          "term": "WordPress",
          "url": "https://shkspr.mobi/blog"
        }
      ]
    },
    {
      "id": "https://shkspr.mobi/blog/?p=75570",
      "title": "[RSS Club] Sorry for breaking your feed readers!",
      "description": "You're part of the Groovy Gang because you're a member of RSS Club! These posts are only available on my RSS and Atom feed. This post is not available in the shops, on the web, via FTP, or anywhere else.  So, yeah, sorry! My last post apparently broke some people's RSS readers.  I had a code sample which said ＜marquee＞ - despite being properly escaped, some feed readers double-decoded it and tur…",
      "url": "https://shkspr.mobi/blog/2026/09/rss-club-sorry-for-breaking-your-feed-readers/",
      "published": "2026-09-15T11:34:26.000Z",
      "updated": "2026-09-15T07:37:02.000Z",
      "content": "<p><mark>You're part of the Groovy Gang because you're a member of <a href=\"https://daverupert.com/rss-club/\">RSS Club</a>! These posts are only available on my RSS and Atom feed. This post is <strong>not</strong> available in the shops, on the web, via FTP, or anywhere else.</mark></p>\n\n<p>So, yeah, sorry! My last post apparently broke some people's RSS readers.  I had a code sample which said <code>＜marquee＞</code> - despite being properly escaped, some feed readers double-decoded it and turned it into a literal marquee element!</p>\n\n<p><video width=\"270\" height=\"585\" muted=\"\" autoplay=\"\" loop=\"\" style=\"display:inline\" src=\"https://shkspr.mobi/blog/wp-content/uploads/2026/09/feedscroll2.webm\"></video><video width=\"270\" height=\"600\" muted=\"\" autoplay=\"\" loop=\"\" style=\"display:inline\" src=\"https://shkspr.mobi/blog/wp-content/uploads/2026/09/feedscroll.webm\"></video?</video></p>\n\n<p>With thanks to Neil and CaféHaine for the videos.</p>\n\n<p>I got several reports that people's readers started scrolling like that and they'd <a href=\"https://github.com/nextcloud/news-android/issues/1719\">raised issues with their feed reader</a>. Ooops! Sorry!</p>\n\n<p>That said, as far as I can tell, the feed <em>is</em> escaped correctly and shouldn't cause problems.</p>\n\n<p>Here's the code (I've added in some spaces to ensure it doesn't cause any issues):</p>\n\n<pre><code class=\"language-xml\"><content type=\"html\">\n   <![CDATA[< p> Lorem ipsum <code>& lt;marquee&gt;</code> dolor sed.</p>\n</code></pre>\n\n<p>So what's going on? The feed is generated by the latest version of WordPress which <a href=\"https://github.com/WordPress/wordpress-develop/blob/99e2de78a828d4fe472e37cf25fb0b2173e65c86/src/wp-includes/feed-atom.php#L89\">uses <code>CDATA</code> to wrap HTML</a> in a feed.</p>\n\n<p>There is a <a href=\"https://core.trac.wordpress.org/ticket/9992\">17 year old discussion about whether this is conformant</a> on the WordPress issue tracker with the conclusion that it isn't incorrect and seems to work fine.</p>\n\n<p>Is it OK? Is my feed broken or are a bunch of readers non-compliant?  Let's go back to basics. The Atom spec says</p>\n\n<blockquote><p>If the value of \"type\" is \"html\", the content of atom:content MUST NOT contain child elements and SHOULD be suitable for handling as <a href=\"https://www.rfc-editor.org/info/rfc4287/#ref-HTML\">HTML</a>.  The HTML markup MUST be escaped; for example, \"<code><br></code>\" as \"<code>&lt;br></code>\".</p>\n\n<p><a href=\"https://www.rfc-editor.org/info/rfc4287/#section-4.1.3.3\">RFC 4287: The Atom Syndication Format</a></p></blockquote>\n\n<p>Hmmmm. That would indicate that ampersand-l-t-semicolon should be interpreted as a less-than sign.</p>\n\n<p>However, the whole thing is wrapped in <code><![CDATA[</code> which according to the XML spec means:</p>\n\n<blockquote><p>CDATA sections may occur anywhere character data may occur; they are used to escape blocks of text containing characters which would otherwise be recognized as markup.</p>\n\n<p><a href=\"https://www.w3.org/TR/REC-xml/#sec-cdata-sect\">Extensible Markup Language (XML) 1.0 (Fifth Edition)</a></p></blockquote>\n\n<p>So I <em>think</em> that a sensible feed-reader should see the CDATA block, grab the HTML inside it, and display it as-is. No need to unescape anything.</p>\n\n<p>That said, I'll see if I can change my feed to <em>not</em> need this hybrid format. There's <a href=\"https://waspdev.com/articles/2026-05-11/avoid-using-cdata-in-rss\">a brilliant blog post by Suren Enfiajyan</a> which makes the case that regular escaping is <em>probably</em> good enough.</p>\n\n<p>If you've experienced this bug - or think that I'm generating my feeds in the wrong way - <a href=\"https://edent.tel\">please get in touch</a>.</p>\n<img src=\"https://shkspr.mobi/blog/wp-content/themes/edent-wordpress-theme/info/okgo.php?ID=75570&HTTP_REFERER=Atom\" alt width=\"1\" height=\"1\" loading=\"eager\">",
      "image": null,
      "media": [],
      "authors": [
        {
          "name": "Terence Eden",
          "email": null,
          "url": "https://edent.tel/"
        }
      ],
      "categories": [
        {
          "label": "RSS Club",
          "term": "RSS Club",
          "url": "https://shkspr.mobi/blog"
        }
      ]
    },
    {
      "id": "https://shkspr.mobi/blog/?p=73143",
      "title": "Esoteric HTML - ismap vs CSS",
      "description": "The HTML specification is old and, while there is beauty in longevity, there's an inevitable build-up of boondoggles and baggage. Some elements like <marquee> have sadly been consigned to the dustbin of history - but there are still vestigial attributes just waiting to trip up the unwary.  If you're young, you may never have heard of Image Maps. Back in the bad-old-days, there weren't many good…",
      "url": "https://shkspr.mobi/blog/2026/09/esoteric-html-ismap-vs-css/",
      "published": "2026-09-14T11:34:53.000Z",
      "updated": "2026-09-14T11:35:05.000Z",
      "content": "<p>The HTML specification is old and, while there is beauty in longevity, there's an inevitable build-up of boondoggles and baggage. Some elements like <code><marquee></code> have sadly been consigned to the dustbin of history - but there are still vestigial attributes just waiting to trip up the unwary.</p>\n\n<p>If you're young, you may never have heard of Image Maps. Back in the bad-old-days, there weren't many good options for laying out a pixel-perfect HTML page. One option was to draw your website in an image editor, load it into a website <em>as an image</em>, and then make certain areas of the image clickable.</p>\n\n<p>One way to do this was to add the attribute <code>ismap</code>. It is <em>only</em> valid on <code><img></code> elements which are inside an <code><a href=…></code> element. Like so:</p>\n\n<pre><code class=\"language-html\"><a href=\"click.php\">\n    <img ismap src=\"img.png\" width=\"100\" height=\"100\">\n</a>\n</code></pre>\n\n<p>When you click on that image, you don't go to <code>click.php</code> - instead you go to <code>click.php?12,34</code> where the two numbers represent the X and Y coordinates of <em>where</em> on the image you clicked. That's brilliant! Your server knows the size of the image - so if you click on the top half it can take you to one place, and if you click in the lower left corner you can go to another.</p>\n\n<p>Brilliant!</p>\n\n<p>Except, of course, there's a catch!</p>\n\n<p>The <a href=\"https://html.spec.whatwg.org/multipage/embedded-content.html#dom-img-ismap\">specification of the <code><img></code> element</a> is a little obtuse. Merely saying:</p>\n\n<blockquote><p>The ismap attribute […] indicates by its presence that the element provides access to a server-side image map. This affects how events are handled on the corresponding a element.</p></blockquote>\n\n<p>Instead, the details are in <a href=\"https://html.spec.whatwg.org/multipage/links.html#links-created-by-a-and-area-elements\">4.6.2 Links created by a and area elements</a>:</p>\n\n<blockquote><p>set x to the distance in CSS pixels from the left edge of the image to the location of the click, and set y to the distance in CSS pixels from the top edge of the image to the location of the click.</p></blockquote>\n\n<p>Did you notice the gotcha?</p>\n\n<blockquote><p><strong>the distance in CSS pixels</strong></p></blockquote>\n\n<p>This is <em>not</em> based on the actual size of the image! It is based on the layout</p>\n\n<p>Let's suppose you have an image which is 100 x 100 pixels. It is added to the website like this:</p>\n\n<p><code><img src=\"100.png\" width=\"100\" height=\"100\" ismap></code></p>\n\n<p>Click on this image and you'll see that your X and Y positions are based on the natural size of the image.</p>\n\n<p><a href=\".\"><img src=\"https://placekittens.com/100/100\" width=\"100\" height=\"100\" ismap=\"\" alt=\"A cute kitten\"></a></p>\n\n<p>But suppose you change the HTML to this:</p>\n\n<p><code><img src=\"100.png\" width=\"500\" height=\"20\" ismap></code></p>\n\n<p>When you click on the image, the X & Y positions are <em>not</em> based on the actual size of the image; they're based on its layout size.</p>\n\n<p><a href=\".\"><img src=\"https://placekittens.com/100/100\" width=\"500\" height=\"20\" ismap=\"\" style=\"height:20px\" alt=\"A distorted image of a kitten\"></a></p>\n\n<p>Suppose you use CSS to resize the image:</p>\n\n<p><code><img src=\"100.png\" width=\"100\" height=\"100\" ismap style=\"width:7em;height:30ch\"></code></p>\n\n<p><a href=\".\"><img src=\"https://placekittens.com/100/100\" width=\"100\" height=\"100\" ismap=\"\" style=\"width:7em;height:30ch\" alt=\"A distorted image of a kitten\"></a></p>\n\n<p>The X and Y aren't based on the image's natural size, nor their declared height and width. Instead they're based on the size on screen determined by CSS.</p>\n\n<p>And, of course, that's not necessarily <em>your</em> CSS! If the user has turned off style sheets, supplied their own, or uses an accessibility tool - the CSS size of the image might be <em>vastly</em> different from what you intended.</p>\n\n<p>If you have an image 100 pixels wide and you want people clicking on the left half to go to a different location to the people clicking on the right half, you might have server-side code which says:</p>\n\n<pre><code class=\"language-_\">if X < 50 :\n    return page1.html\nelse\n    return page2.html\n</code></pre>\n\n<p>But if the CSS has stretched, shrunk, skewed, or distorted the image then you have <em>no way of knowing</em> where the user clicked.</p>\n\n<p>As far as I can tell, this behaviour is the same in all major browsers.</p>\n\n<p>Basically, what I'm saying is, don't use <code>ismap</code> unless you're absolutely sure that there will be no CSS shenanigans. Even then, it probably isn't worth the risk.</p>\n<img src=\"https://shkspr.mobi/blog/wp-content/themes/edent-wordpress-theme/info/okgo.php?ID=73143&HTTP_REFERER=Atom\" alt width=\"1\" height=\"1\" loading=\"eager\">",
      "image": null,
      "media": [],
      "authors": [
        {
          "name": "Terence Eden",
          "email": null,
          "url": "https://edent.tel/"
        }
      ],
      "categories": [
        {
          "label": "css",
          "term": "css",
          "url": "https://shkspr.mobi/blog"
        },
        {
          "label": "HTML5",
          "term": "HTML5",
          "url": "https://shkspr.mobi/blog"
        },
        {
          "label": "webdev",
          "term": "webdev",
          "url": "https://shkspr.mobi/blog"
        }
      ]
    },
    {
      "id": "https://shkspr.mobi/blog/?p=73168",
      "title": "The expectations of privacy in driverless cars",
      "description": "Do riders in autonomous vehicles think that they are in a private space? Here's a fascinating story from California where an robotaxi was redirected from its intended destination and, instead, delivered its misbehaving passengers to the police.  The 15-year-old passengers were riding in a driverless autonomous car around San Mateo Monday afternoon. The teens drank alcohol inside the Waymo taxi…",
      "url": "https://shkspr.mobi/blog/2026/09/the-expectations-of-privacy-in-driverless-cars/",
      "published": "2026-09-13T11:34:13.000Z",
      "updated": "2026-09-13T11:33:41.000Z",
      "content": "<p>Do riders in autonomous vehicles think that they are in a private space? Here's a fascinating story from California where an robotaxi was redirected from its intended destination and, instead, delivered its misbehaving passengers to the police.</p>\n\n<blockquote><p>The 15-year-old passengers were riding in a driverless autonomous car around San Mateo Monday afternoon. The teens drank alcohol inside the Waymo taxi and shot Orbeez beads with a toy gun toward other vehicles.</p>\n\n<p>A Waymo employee, who was remotely monitoring the car, tricked the unruly teenagers, authorities said. The employee told the young passengers that the Waymo was having mechanical issues and needed to stop.</p>\n\n<p>Unknown to the teens, the employee had also called the San Mateo Police Department to report that a gun was firing from the car.</p>\n\n<p><a href=\"https://www.kron4.com/news/bay-area/heres-how-waymo-tricked-unruly-teen-passengers-in-san-mateo/\">Here’s how Waymo tricked unruly teen passengers in San Mateo</a></p></blockquote>\n\n<p>Is that OK?</p>\n\n<p>Kids shooting (albeit fake) guns out of cars is bad. I've no problem with the long arm of the law feeling their collars.</p>\n\n<p>But what sort of reasonable expectation of privacy do you have when you jump into a driverless car?</p>\n\n<p>If you have a blazing row with your partner while sat in the back of a black cab, the driver's going to hear, right? There's no privacy expectation although you might rely on their discretion.</p>\n\n<p>Take a phone call and arrange a drug deal, the driver might turn you in to the police. They're not a confidant, are they?</p>\n\n<p>Kiss someone you shouldn't and you accept the risk that the driver might both notice and care.</p>\n\n<p>But when there's no driver, there's no risk of your privacy being invaded is there?</p>\n\n<blockquote><p>Nine former Tesla employees told Reuters that Tesla workers shared customer videos and images recorded by in-car cameras between 2019 and 2022.</p>\n\n<p><a href=\"https://observer.com/2023/04/tesla-camera-recording-privacy-concern/\">Tesla Workers Shared ‘Intimate’ Videos Recorded By In-Car Cameras</a></p></blockquote>\n\n<p>Ah.</p>\n\n<p>I don't know how Waymo was alerted to the problems in the car. Perhaps someone called them and reported the numberplate. Perhaps the car heard raised voices and sent an alert. Perhaps Waymo just regularly drops in on all its customers.</p>\n\n<p>Rummaging through Waymo's various privacy policies eventually leads to this <a href=\"https://support.google.com/waymo/answer/9190819\">rather ambiguous page</a> which describes how they monitor the inside of their vehicles.</p>\n\n<blockquote><p>Our autonomous vehicles are equipped with an advanced suite of sensors – including cameras and microphones – that act as the 'eyes and ears' of our Waymo Driver.</p>\n\n<strong>Cameras inside the car</strong>\n\n<p>Cameras are a way for us to make sure that your trip goes smoothly. Among other things, we may use cameras to:</p>\n\n<ul>\n  <li>Make sure that cars are clean</li>\n  <li>Find lost items</li>\n  <li>Provide help in case of emergency</li>\n  <li><i>Check that in-car rules are being followed</i> <small>[Emphasis added]</small></li>\n  <li>Improve products and services</li>\n  <li><i>Promote safety and security</i> <small>[Emphasis added]</small></li>\n</ul>\n\n<p>Our Support team may review video under certain circumstances, including after an issue is brought to our attention. Occasionally, in more urgent circumstances, Support may access live video during a trip.</p>\n\n<strong>Microphones inside the car</strong>\n\n<p>The microphones inside the car are only on during voice calls with Rider Support or when you actively choose to enable microphones inside the car.</p></blockquote>\n\n<p>To me, that sounds like riders' voices aren't automatically sent back to the mothership. Indeed, they're at pains to say:</p>\n\n<blockquote><p>Waymo vehicles also have a number of sensors, including our audio-detection system used to detect police and emergency vehicle sirens. Waymo has implemented technical and procedural safeguards designed to limit the collection of any human voice data from these microphones.</p></blockquote>\n\n<p>So there is <em>some</em> acknowledgement of privacy - for our voices at least. Meanwhile, passengers are <a href=\"https://www.brautiganarchives.xyz/machines.html\">all watched over by machines of loving grace</a> or, at the very least, fallible humans with prurient interests.</p>\n\n<p>About a decade ago, people were theorising that a driverless cars would one day deliver to you <a href=\"https://www.reddit.com/r/Showerthoughts/comments/5qg125/eventually_a_selfdriving_car_will_deliver_a_dead/\">a rider who died on the journey</a>. I don't think that's happened yet - instead, we have cars watching what what we do. Silently judging us picking our noses. Examining our body language for signs of stress. Tracking our breathing patterns and heart-rates to ensure we aren't going to cause damage to the vehicle.</p>\n\n<p>Not listening though. That would be a step too far.</p>\n\n<p>Besides, who needs to use a microphone when you've got a high-resolution camera backed by AI?</p>\n\n<p></p><div style=\"width: 620px;\" class=\"wp-video\"><video class=\"wp-video-shortcode\" id=\"video-73168-2\" width=\"620\" height=\"349\" preload=\"metadata\" controls=\"controls\"><source type=\"video/mp4\" src=\"https://shkspr.mobi/blog/wp-content/uploads/2026/09/2001-lip-reading-web.mp4?_=2\"><a href=\"https://shkspr.mobi/blog/wp-content/uploads/2026/09/2001-lip-reading-web.mp4\">https://shkspr.mobi/blog/wp-content/uploads/2026/09/2001-lip-reading-web.mp4</a></video></div><p></p>\n\n<p>Just as I finished writing this post, a story broke about how a <a href=\"https://www.latimes.com/california/story/2026-09-12/juveniles-riding-in-waymo-arrested-after-police-find-ghost-gun\">Waymo pulled over and called the police on riders who had \"ghost gun\"</a>. The company said it alerted the authorities after detecting a terms of service violation.</p>\n\n<p>Of course, it didn't say <em>how</em> it detected that!</p>\n\n<p>I also find it curious that in both cases, the alleged perpetrators were juveniles. Maybe children have less of a right to privacy than adults?</p>\n\n<p>I guess when you ride alone, you ride with a snitch.</p>\n<img src=\"https://shkspr.mobi/blog/wp-content/themes/edent-wordpress-theme/info/okgo.php?ID=73168&HTTP_REFERER=Atom\" alt width=\"1\" height=\"1\" loading=\"eager\">",
      "image": null,
      "media": [
        {
          "url": "https://shkspr.mobi/blog/wp-content/uploads/2026/09/2001-lip-reading-web.mp4",
          "image": null,
          "title": null,
          "length": 3454412,
          "type": "video",
          "mimeType": "video/mp4"
        }
      ],
      "authors": [
        {
          "name": "Terence Eden",
          "email": null,
          "url": "https://edent.tel/"
        }
      ],
      "categories": [
        {
          "label": "AI",
          "term": "AI",
          "url": "https://shkspr.mobi/blog"
        },
        {
          "label": "automation",
          "term": "automation",
          "url": "https://shkspr.mobi/blog"
        },
        {
          "label": "car",
          "term": "car",
          "url": "https://shkspr.mobi/blog"
        },
        {
          "label": "privacy",
          "term": "privacy",
          "url": "https://shkspr.mobi/blog"
        },
        {
          "label": "robots",
          "term": "robots",
          "url": "https://shkspr.mobi/blog"
        }
      ]
    },
    {
      "id": "https://shkspr.mobi/blog/?p=74470",
      "title": "ActivityPub - How to send an updated user profile to Mastodon and the Fediverse",
      "description": "Let's suppose you've updated the description of your ActivityPub account from \"World's Number 1 Taylor Swift Fan\" to \"This account is now a Nickleback Truther\". How do you let the rest of the Fediverse know that you've changed your allegiance?  By default, most Mastodon instances won't periodically poll your account information just to see if you've updated it. So how does the information get…",
      "url": "https://shkspr.mobi/blog/2026/09/activitypub-how-to-send-an-updated-user-profile-to-mastodon-and-the-fediverse/",
      "published": "2026-09-12T11:34:02.000Z",
      "updated": "2026-09-13T06:08:41.000Z",
      "content": "<p>Let's suppose you've updated the description of your ActivityPub account from \"World's Number 1 Taylor Swift Fan\" to \"This account is now a Nickleback Truther\". How do you let the rest of the Fediverse know that you've changed your allegiance?</p>\n\n<p>By default, most Mastodon instances won't periodically poll your account information just to see if you've updated it. So how does the information get from your server to your followers' servers?</p>\n\n<p>This wasn't immediately obvious to me, but I got a clue from reading <a href=\"https://shkspr.mobi/blog/2026/09/book-review-activitypub-by-evan-prodromou/\">Evan Prodromou's book on ActivityPub</a>:</p>\n\n<blockquote><p>The Update activity type is for updating the properties of an object represented by the object property.</p>\n\n<p>The most common types of objects that can be updated are content objects, like Note or Image. Actor types (like Person) and Question activity types can also be updated.</p></blockquote>\n\n<p>Aha!</p>\n\n<p>You need to craft an <code>Update</code> message which has as its object the <em>new</em> user information. That needs to be sent to the inbox of all your followers.</p>\n\n<p>Something like this:</p>\n\n<pre><code class=\"language-json\">{\n    \"@context\": \"https://www.w3.org/ns/activitystreams\",\n    \"actor\": \"https://example.com/user\",\n    \"id\": \"6a9162a6-a8e5-ca0f-9c08-8e6b814acef8\",\n    \"published\": \"2026-08-31T12:34:56+01:00\",\n    \"to\": \"https://www.w3.org/ns/activitystreams#Public\",\n    \"type\": \"Update\",\n    \"object\": {\n        \"@context\": [\n            \"https://www.w3.org/ns/activitystreams\",\n            \"https://w3id.org/security/v1\"\n        ],\n        \"id\": \"https://example.com/user\",\n        \"name\": \"My new name\",\n        \"summary\": \"A brand new description!\",\n        …\n    },\n}\n</code></pre>\n\n<p>Obviously the <em>full</em> user information is a bit more than that - it will include inbox details, public keys, avatars, etc. The <code>published</code> property in the Update activity should be when you changed your details - not when the account was created.</p>\n\n<p>Once that was sent, Mastodon immediately reflected the changes.</p>\n\n<h2 id=\"thanks-to-nlnet\"><a href=\"https://shkspr.mobi/blog/2026/09/activitypub-how-to-send-an-updated-user-profile-to-mastodon-and-the-fediverse/#thanks-to-nlnet\">Thanks to NLnet</a></h2>\n\n<p>This blog post was funded in part by the work I'm doing for my NLnet NGI0 grant to develop <a href=\"https://gitlab.com/edent/activity-bot\">ActivityBot</a>.</p>\n\n<p><a href=\"https://nlnet.nl/project/ActivityBot/\"><img src=\"https://shkspr.mobi/blog/wp-content/uploads/2026/08/NGI-logos.webp\" alt=\"NLnet logo.\" width=\"900\" height=\"200\" class=\"aligncenter\"></a></p>\n<img src=\"https://shkspr.mobi/blog/wp-content/themes/edent-wordpress-theme/info/okgo.php?ID=74470&HTTP_REFERER=Atom\" alt width=\"1\" height=\"1\" loading=\"eager\">",
      "image": null,
      "media": [],
      "authors": [
        {
          "name": "Terence Eden",
          "email": null,
          "url": "https://edent.tel/"
        }
      ],
      "categories": [
        {
          "label": "ActivityBot",
          "term": "ActivityBot",
          "url": "https://shkspr.mobi/blog"
        },
        {
          "label": "ActivityPub",
          "term": "ActivityPub",
          "url": "https://shkspr.mobi/blog"
        },
        {
          "label": "fediverse",
          "term": "fediverse",
          "url": "https://shkspr.mobi/blog"
        },
        {
          "label": "mastodon",
          "term": "mastodon",
          "url": "https://shkspr.mobi/blog"
        }
      ]
    },
    {
      "id": "https://shkspr.mobi/blog/?p=74757",
      "title": "[RSS Club] Sneak peek at new DOI functionality",
      "description": "If you're reading this, you're part of RSS Club! A top secret society of cool people who subscribe to my feed. This post is not available on the web or via email.  I've been playing about with Rogue Scholar. It's an open-access publication which allows blogs to get a persistent Digital Object Identifier.  If I've set everything up correctly (not a given) then all new posts on this site will be…",
      "url": "https://shkspr.mobi/blog/2026/09/rss-club-sneak-peek-at-new-doi-functionality/",
      "published": "2026-09-11T11:34:12.000Z",
      "updated": "2026-09-11T09:48:42.000Z",
      "content": "<p><mark>If you're reading this, you're part of <a href=\"https://daverupert.com/rss-club/\">RSS Club</a>! A <em>top secret</em> society of cool people who subscribe to my feed. This post is <strong>not</strong> available on the web or via email.</mark></p>\n\n<p>I've been playing about with <a href=\"https://rogue-scholar.org/\">Rogue Scholar</a>. It's an open-access publication which allows blogs to get a persistent <a href=\"https://en.wikipedia.org/wiki/Digital_object_identifier\">Digital Object Identifier</a>.</p>\n\n<p>If I've set everything up correctly (not a given) then all new posts on this site will be issued with a DOI. Hopefully, this will not include RSS Club posts - as I'd like to keep them as a special private treat just between you and me.</p>\n\n<p>I'm in the process of writing a WordPress plugin to retrieve the DOI and add it to posts. I'm not sure if there's a sensible way to add it into an RSS feed, but I'll give it a go.</p>\n\n<p>Will this be useful? I don't know. My posts sometimes get <a href=\"https://shkspr.mobi/blog/citations\">referenced in proper academic works</a> - I'm not sure if this'll make any difference to that. But it is nice to experiment with these things.</p>\n\n<p>If you have any experience with DOI or Rogue Scholar - please <a href=\"https://edent.tel/\">get in touch</a>.</p>\n\n<p>Thanks for being a member of RSS Club - you rock 😃</p>\n<img src=\"https://shkspr.mobi/blog/wp-content/themes/edent-wordpress-theme/info/okgo.php?ID=74757&HTTP_REFERER=Atom\" alt width=\"1\" height=\"1\" loading=\"eager\">",
      "image": null,
      "media": [],
      "authors": [
        {
          "name": "Terence Eden",
          "email": null,
          "url": "https://edent.tel/"
        }
      ],
      "categories": [
        {
          "label": "RSS Club",
          "term": "RSS Club",
          "url": "https://shkspr.mobi/blog"
        }
      ]
    },
    {
      "id": "https://shkspr.mobi/blog/?p=68346",
      "title": "Put an AV test at the start of your slides",
      "description": "For years, I've had a test-card at the start of my slides. Before I start my talk, I can immediately see if the aspect ratio is wrong, colours are off, or any other visual issues with the presentation.    A few years ago I was invited to give a talk and was assured that the venue was set up for audio as well as video. I dutifully filled my slides with with demo videos containing sound. None of…",
      "url": "https://shkspr.mobi/blog/2026/09/put-an-av-test-at-the-start-of-your-slides/",
      "published": "2026-09-10T11:34:10.000Z",
      "updated": "2026-09-02T09:08:33.000Z",
      "content": "<p>For years, I've had a <a href=\"https://shkspr.mobi/blog/2017/11/put-a-test-card-at-the-start-of-your-slides/\">test-card at the start of my slides</a>. Before I start my talk, I can immediately see if the aspect ratio is wrong, colours are off, or any other visual issues with the presentation.</p>\n\n<img src=\"https://shkspr.mobi/blog/wp-content/uploads/2017/10/Test-Card-on-a-screen.jpg\" alt=\"A test card is displaying on a television screen\" width=\"1024\" height=\"768\" class=\"alignleft size-full wp-image-28772\">\n\n<p>A few years ago I was invited to give a talk and was assured that the venue was set up for audio as well as video. I dutifully filled my slides with with demo videos containing sound. None of them worked. Somewhere between the HDMI output of the presentation laptop and the speakers, the audio went <abbr title=\"Absent Without Leave\">AWOL</abbr>.</p>\n\n<p>Ever since then, I've placed an audio test slide at the start of my presentations. There's <a href=\"https://www.youtube.com/results?search_query=sound+sync+test\">a good range of videos on YouTube</a> - pick one you like, embed it into your slides, and play it before your talk starts.</p>\n\n<p>Over the years, I've found the following \"bugs\" with event AV setups:</p>\n\n<ul>\n<li>No sound.</li>\n<li>Only left channel working.</li>\n<li>Severe latency between audio and video.</li>\n<li>Garbled sound.</li>\n<li>Sound routing to the room but not the livestream.</li>\n<li>Feedback / howl around when sound playing.</li>\n</ul>\n\n<p>Whether events are professionally run or community managed, you can never guarantee that sound will work. Add subtitles to your videos. If possible, add a sign-language interpreter. And, if all else fails, hold your microphone to your laptop's speakers.</p>\n<img src=\"https://shkspr.mobi/blog/wp-content/themes/edent-wordpress-theme/info/okgo.php?ID=68346&HTTP_REFERER=Atom\" alt width=\"1\" height=\"1\" loading=\"eager\">",
      "image": null,
      "media": [],
      "authors": [
        {
          "name": "Terence Eden",
          "email": null,
          "url": "https://edent.tel/"
        }
      ],
      "categories": [
        {
          "label": "presentations",
          "term": "presentations",
          "url": "https://shkspr.mobi/blog"
        }
      ]
    },
    {
      "id": "https://shkspr.mobi/blog/?p=74622",
      "title": "ActivityPub - Is it worth defending against replay attacks and message/signature time skew?",
      "description": "Here's a problem that I've found with ActivityBot - my little ActivityPub server. Sometimes it receives messages which were originally sent months ago. Why does that happen and is it risky to accept and process them?  My tl;dr is that it probably isn't worth worrying about. But I'd love someone to tell me why I'm wrong.  Here's my thinking:  Table of ContentsCausesIs that a problem?What are we…",
      "url": "https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/",
      "published": "2026-09-08T11:34:51.000Z",
      "updated": "2026-09-08T09:42:04.000Z",
      "content": "<p>Here's a problem that I've found with <a href=\"https://gitlab.com/edent/activity-bot/\">ActivityBot</a> - my little ActivityPub server. Sometimes it receives messages which were originally sent <em>months</em> ago. Why does that happen and is it risky to accept and process them?</p>\n\n<p>My tl;dr is that it <em>probably</em> isn't worth worrying about. But I'd love someone to tell me why I'm wrong.</p>\n\n<p>Here's my thinking:</p>\n\n<p></p><nav role=\"doc-toc\"><menu><li><h2 id=\"table-of-contents\"><a href=\"https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#table-of-contents\">Table of Contents</a></h2><menu><li><a href=\"https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#causes\">Causes</a></li><li><a href=\"https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#is-that-a-problem\">Is that a problem?</a></li><li><a href=\"https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#what-are-we-trying-to-protect-against\">What are we trying to protect against?</a></li><li><a href=\"https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#putting-it-all-together\">Putting it all together</a></li><li><a href=\"https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#no-youre-wrong-and-i-can-prove-it\">No! You're wrong and I can prove it!</a></li></menu></li></menu></nav><p></p>\n\n<h2 id=\"causes\"><a href=\"https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#causes\">Causes</a></h2>\n\n<p>All ActivityPub messages should have a \"published\" timestamp in their body. Some will have an \"updated\" timestamp. That tells you, unsurprisingly, when the message is alleged to have been originally published or updated. That time might be very different to the time you receive the message.</p>\n\n<p>There are, I think, three different reasons why a server might receive a message which has an out-of-date timestamp.</p>\n\n<p>The first is that sometimes servers are just slow. Processing thousands of messages at the same time means that some of those messages take a while to send.  <a href=\"https://shkspr.mobi/blog/2023/09/how-far-did-my-post-go-on-the-fediverse/\">ActivityPub is one big chain-mail</a> so it can take several minutes for a message to be sent to all your followers.</p>\n\n<p>Similarly, your server might be slow. If it doesn't acknowledge receipt of a message, the original server will try sending it again. Sometimes that can take a while.</p>\n\n<p>Finally, some servers take a relaxed view of standards. They send an update to an old message but keep the original publication date. Ideally, they'd use an \"updated\" timestamp but quite often they don't.</p>\n\n<p>For the purposes of checking the legitimacy of the message, <strong>you do not need to check when a message says it was published or updated</strong>. You might want to check it isn't an <em>obviously</em> bogus date like far in the future or impossibly far in the past - but that's up to you.</p>\n\n<p>It is normal that your server receives messages which appear to have been published at a totally different time from now.</p>\n\n<h2 id=\"is-that-a-problem\"><a href=\"https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#is-that-a-problem\">Is that a problem?</a></h2>\n\n<p><em>Probably</em> not.</p>\n\n<p>As described above, there are various reasons why a message may be delayed in transit - or may appear to come from the distant past.</p>\n\n<p>What we <em>can</em> check is when the message was cryptographically signed by the sending server. This is independent of its published or updated timestamp.</p>\n\n<p>HTTP requests to your server will have a <code>date</code> header which looks like <code>Tue, 01 Sep 2026 15:54:21 GMT</code> - this is in the slightly peculiar and Anglocentric <a href=\"https://www.rfc-editor.org/info/rfc5322/#section-3.3\">RFC 5322 format</a>.</p>\n\n<p>New style RFC 9421 headers will also have a <code>signature-input</code> header which will contain something like <code>created=1788278061</code>. That uses the slightly obscure <a href=\"https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap04.html#tag_04_16\">UNIX / POSIX time</a> which counts seconds since the \"Epoch\" of 1st January 1970.</p>\n\n<p>If you <a href=\"https://www.epochconverter.com/\">convert the UNIX time</a> to something more modern, you should get an <em>identical</em> value to the <code>date</code> header.</p>\n\n<p>But that isn't always the case. For example, <a href=\"https://www.rfc-editor.org/rfc/rfc9421.html#:~:text=Tue%2C%2020%20Apr%202021%2002%3A07%3A55%20GMT,-Content%2DType\">the RFC 9421 standard gives this example</a>:</p>\n\n<pre><code class=\"language-_\">Date: Tue, 20 Apr 2021 02:07:55 GMT\n\"@signature-params\": (\"@method\" \"@authority\" \"@path\" \\\n  \"content-digest\" \"content-length\" \"content-type\")\\\n  ;created=1618884473;keyid=\"test-key-rsa-pss\"\n</code></pre>\n\n<p>Converting <code>1618884473</code> to normal time gives Tue, 20 Apr 2021 02:07:<strong>53</strong> - a two second difference.</p>\n\n<p>If the <code>date</code> and <code>created</code> values differ significantly - that may indicate that the message is untrustworthy. Or that there was a delay between the signing and the sending.</p>\n\n<p>The spec says:</p>\n\n<blockquote><p>The Date header field value represents the timestamp of the HTTP message. However, the creation time of the signature itself is encoded in the created signature parameter. These two values can be different, depending on how the signature and the HTTP message are created and serialized. Applications processing signatures for valid time windows should use the created signature parameter for such calculations. An application could also put limits on how much skew there is between the Date field and the created signature parameter, in order to limit the application of a generated signature to different HTTP messages.</p>\n\n<p><a href=\"https://www.rfc-editor.org/rfc/rfc9421.html#section-7.2.4\">7.2.4. Choosing Signature Parameters and Derived Components over HTTP Fields</a></p></blockquote>\n\n<p>But, of course, it doesn't tell you how much skew is problematic. It's up to you how much skew you're prepared to accept.</p>\n\n<p>So that's the difference between the sent time and the signed time. The next time to check is your own. As we've discussed, sometimes servers are slow sending things out. Would you accept a request that was signed five minutes ago? Five days ago? Five months ago? What amount of difference is dangerous?</p>\n\n<p>Here's what various services and sages have to say:</p>\n\n<h3 id=\"mastodon\"><a href=\"https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#mastodon\">Mastodon</a></h3>\n\n<blockquote><p>The request contains a Date header. Compare it with current date and time within a reasonable time window to prevent replay attacks.</p>\n\n<p><a href=\"https://blog.joinmastodon.org/2018/07/how-to-make-friends-and-verify-requests/\">How to make friends and verify requests</a></p></blockquote>\n\n<p>What is \"reasonable\"? The <a href=\"https://github.com/mastodon/mastodon/blob/89bc0eb42609463d4b11e1604dacc37332a0f5ab/app/lib/signed_request.rb#L5\">source code</a> suggests one hour.</p>\n\n<h3 id=\"grishka\"><a href=\"https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#grishka\">Grishka</a></h3>\n\n<blockquote><p>Time in the Date header must differ from the recipient server’s clock by no more than 30 seconds</p>\n\n<p><a href=\"https://grishka.me/blog/activitypub-from-scratch/\">A bare-minimum ActivityPub server from scratch</a></p></blockquote>\n\n<h3 id=\"evan-prodromou\"><a href=\"https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#evan-prodromou\">Evan Prodromou</a></h3>\n\n<blockquote><p><code>static #maxDateDiff = 5 * 60 * 1000 // 5 minutes</code></p>\n\n<p><a href=\"https://github.com/evanp/activitypub-bot/blob/main/lib%2Fhttpsignatureauthenticator.js#L8\">activitypub-bot</a></p></blockquote>\n\n<h3 id=\"swicg\"><a href=\"https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#swicg\">SWICG</a></h3>\n\n<blockquote><p>The standards don't give a concrete time window to use for this comparison. In practice, an hour plus a few minutes buffer in either direction may be a good value, to account for both clock skew and differences in time zone/daylight savings time configuration across systems.</p>\n\n<p><a href=\"https://swicg.github.io/activitypub-http-signature/#how-to-verify-a-signature\">How To Verify a Signature</a></p></blockquote>\n\n<h3 id=\"others\"><a href=\"https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#others\">Others</a></h3>\n\n<p>Without naming names, it looks like a bunch of popular servers don't check whether there's a significant difference between the date the request was signed and the date it was received.</p>\n\n<h3 id=\"summary\"><a href=\"https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#summary\">Summary</a></h3>\n\n<p>Various documents and implementations recommend anything between 30 seconds to \"a bit more than 60 minutes\". Or they just ignore any date difference.</p>\n\n<p>What's the right answer? What happens if the signed date is significantly different from the current date?</p>\n\n<h2 id=\"what-are-we-trying-to-protect-against\"><a href=\"https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#what-are-we-trying-to-protect-against\">What are we trying to protect against?</a></h2>\n\n<p>Replay Attacks. Suppose someone is listening to the communications between the sending server and your server. They copy the message that is sent to you. Later they send it again!</p>\n\n<p>At this point, you might be thinking \"so what?\" and… I'm inclined to agree with you!</p>\n\n<p>What's the worst that could happen if you received the same message multiple times? Two things that I can think of.</p>\n\n<p>Firstly, it might <em>not</em> be the same message. It is possible to send a new message but with old headers. An attacker could make someone post \"I hate Taylor Swift\" against their will and watch as legions of fans disembowel the victim.</p>\n\n<p>Except, I don't think this is likely. The signature in the header contains a hash of the message being sent. If you are properly validating the signature, a changed message will have a different hash from the one in the original message. You don't need to check timestamps, you just need to check if the hashes match.</p>\n\n<p>Secondly, <a href=\"https://www.freecodecamp.org/news/idempotence-explained\">idempotence</a>. That's a fancy word for \"pressing the button multiple times should only result in one action\".</p>\n\n<p>What happens if a user appears to send you multiple \"like\" messages for a single post? You only record one like.</p>\n\n<p>What if they send multiple messages with the same content? Well, each will have a unique ID in the message - so you only post it once.</p>\n\n<p>What if they send multiple <em>anythings</em>? I can't think of any ActivityPub action which would not be idempotent.</p>\n\n<p>About the worst thing I can think of is this:</p>\n\n<ul>\n<li>Alice sends a message to you saying \"I want to follow Bob\".</li>\n<li>Mallory intercepts this message.</li>\n<li>You record Alice is now following Bob.</li>\n<li>Alice sends a message to you saying \"I want to <em>unfollow</em> Bob\".</li>\n<li>You record the severed relationship.</li>\n<li>Mallory replays the original follow message.</li>\n<li>You record Alice is now following Bob.</li>\n</ul>\n\n<p>It's also possible the following could happen:</p>\n\n<ul>\n<li>Alice posts a message saying \"I love The Beatles\".</li>\n<li>You record Alice's message and display it on the timeline.</li>\n<li>Alice updates her post to say \"I love the Rolling Stones\".</li>\n<li>Mallory intercepts this message.</li>\n<li>You record Alice's updated message and display the new version on the timeline.</li>\n<li>Alice updates her post yet again to say \"I love the Spice Girls\".</li>\n<li>You record Alice's updated message and display the new version on the timeline.</li>\n<li>Mallory replays the original update message.</li>\n<li>You now display that Alice loves the Stones rather than Spice Girls.</li>\n</ul>\n\n<p>Perhaps the same can happen with like/unlike, block/unblock, boost/unboost.</p>\n\n<p>But none of that is significantly prevented by checking the date.</p>\n\n<p>Ultimately, it is up to your sever to check the unique ID of each message and refuse to action any repeated messages. You may not want to trust the unique ID which is sent with the message. If that's the case, you can calculate your own - perhaps using a hash of the contents, the signature, or some other process which will generate an ID based on the message.</p>\n\n<h2 id=\"putting-it-all-together\"><a href=\"https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#putting-it-all-together\">Putting it all together</a></h2>\n\n<p>Here's what you need to do to prevent replay attacks:</p>\n\n<ol>\n<li>Independently calculate the hash of the message received.</li>\n<li>Validate that your calculated hash matches the hash sent in the message's HTTP headers.\n\n<ul>\n<li>If not, this is a potential replay attack and the message must be ignored.</li>\n</ul></li>\n<li>Verify that the signature received in the message's HTTP headers includes the message hash and is cryptographically valid.\n\n<ul>\n<li>If not, the signature is invalid  and the message must be ignored.</li>\n</ul></li>\n<li>Has the received message's unique ID already been processed?\n\n<ul>\n<li>If so, refuse to process it again.</li>\n</ul></li>\n</ol>\n\n<p>I don't see what checking the timestamp of the HTTP signature has to do with anything. Someone who has access to the original messages and their headers could send them milliseconds after the original delivery.</p>\n\n<p>I think it is probably <em>pragmatic</em> to give messages 60ish minutes grace before dropping them. Delays happen, but anything more significant than an hour <em>might</em> indicate a attack. But, equally, might just mean that the Internet is having a slow day.</p>\n\n<p>If you are correctly checking signatures and hashes, I don't think you need to worry about skew between signature date and delivery date.</p>\n\n<h2 id=\"no-youre-wrong-and-i-can-prove-it\"><a href=\"https://shkspr.mobi/blog/2026/09/activitypub-is-it-worth-defending-against-replay-attacks-and-message-signature-time-skew/#no-youre-wrong-and-i-can-prove-it\">No! You're wrong and I can prove it!</a></h2>\n\n<p>Please tell me where I have erred! Stick a comment in the box or drop me an email. If I've made a massive or subtle mistake, I'd love to know what.</p>\n<img src=\"https://shkspr.mobi/blog/wp-content/themes/edent-wordpress-theme/info/okgo.php?ID=74622&HTTP_REFERER=Atom\" alt width=\"1\" height=\"1\" loading=\"eager\">",
      "image": null,
      "media": [],
      "authors": [
        {
          "name": "Terence Eden",
          "email": null,
          "url": "https://edent.tel/"
        }
      ],
      "categories": [
        {
          "label": "ActivityBot",
          "term": "ActivityBot",
          "url": "https://shkspr.mobi/blog"
        },
        {
          "label": "ActivityPub",
          "term": "ActivityPub",
          "url": "https://shkspr.mobi/blog"
        },
        {
          "label": "http",
          "term": "http",
          "url": "https://shkspr.mobi/blog"
        },
        {
          "label": "security",
          "term": "security",
          "url": "https://shkspr.mobi/blog"
        }
      ]
    },
    {
      "id": "https://shkspr.mobi/blog/?p=74588",
      "title": "The purpose of DNS is to spread scams",
      "description": "I imagine everyone here has received an unsolicited message telling them that their tax is overdue and that they urgently need to visit Genuine-Tax-Payment-Website.fart or that a parcel is delayed at customs and you can pay a small sum for its release at Almost-The-Right-Acronym.ak  You know it is a scam. Most people just mark as spam and move on with their day. But a significant number of people …",
      "url": "https://shkspr.mobi/blog/2026/09/the-purpose-of-dns-is-to-spread-scams/",
      "published": "2026-09-06T11:34:20.000Z",
      "updated": "2026-09-05T17:12:13.000Z",
      "content": "<p>I imagine everyone here has received an unsolicited message telling them that their tax is overdue and that they urgently need to visit Genuine-Tax-Payment-Website.fart or that a parcel is delayed at customs and you can pay a small sum for its release at Almost-The-Right-Acronym.ak</p>\n\n<p>You know it is a scam. Most people just mark as spam and move on with their day. But a significant number of people don't. They hastily visit the site, tap in their credit card details, give it their mother's maiden name, confirm address, upload a nude selfie, and only then realise that they've been had.</p>\n\n<p>The Internet works at pretty close to the speed of light. You can register a .uk domain and a minute later it's accessible from the other side of the planet. Brilliant for users who want to quickly launch a website. Also brilliant for abusers who want to launch a spam campaign.</p>\n\n<p>By the time enough people have reported the scammers' domain as suspicious, it is too late. In the time it takes for a registrar to disable the domain, or for its name to make its way to the <a href=\"https://safebrowsing.google.com/\">Safe Browsing List</a>, a million messages have already been sent and enough people have handed over their details.</p>\n\n<p>We're told that \"<a href=\"https://en.wikipedia.org/wiki/The_purpose_of_a_system_is_what_it_does\">the purpose of a system is what it does</a>\". At the moment, the Domain Name System's purpose seems to be a vector for criminals to run scams on people at a terrifyingly high rate.</p>\n\n<h2 id=\"how-big-is-this-problem\"><a href=\"https://shkspr.mobi/blog/2026/09/the-purpose-of-dns-is-to-spread-scams/#how-big-is-this-problem\">How big is this problem?</a></h2>\n\n<p>BIG!</p>\n\n<p>There's a great blog post by Andrew Campling which reports on this startling claim:</p>\n\n<blockquote><p>The study found that at least 10% of all new gTLD domain names registered during the year had subsequently appeared on security blocklists by the time of analysis. It estimated that, taking account of subsequent blocklisting and associated domains not themselves blocklisted, the share of names registered by malicious actors <strong>may be closer to 20%</strong>.</p>\n\n<p><a href=\"https://labs.ripe.net/author/andrew_campling/dns-abuse-and-criminal-infrastructure-beyond-definitions-and-blocklists/\">DNS Abuse and Criminal Infrastructure: Beyond Definitions and Blocklists</a> (emphasis added)</p></blockquote>\n\n<p>That links to a presentation by Interisle which contains some rather shocking statistics (<a href=\"https://www.icann.org/en/blogs/details/looking-beyond-the-numbers-understanding-malicious-domain-registration-data-10-08-2026-en\">albeit with disputed methodology</a>). It looks at <em>generic</em> Top Level Domains (gTLD) - those are things like .com and .fun rather than country code TLDs (ccTLD) like .uk and .de.</p>\n\n<p>It says 85 million new registrations of gTLDs were made in 2025. Of those 8.5 million were added to blocklists by May 2025. It reckons that a 10% abuse rate is the likely floor for these numbers and it's probably closer to 20%. One in five newly registered domains with a gTLD are scams. That's a bloody crisis.</p>\n\n<p>13 TLDs had more than 50% of their registrations blocklisted.</p>\n\n<img src=\"https://shkspr.mobi/blog/wp-content/uploads/2026/08/gTLDs.webp\" alt=\"Table listing the top 13 generic Top-Level Domains (gTLDs) with the highest percentage of blocklisted, malicious new domains created in 2025. Ranked from highest to lowest blocklist percentage, top entries include .LOCKER (72.9%), .LGBT (72.2%), and .TOWN (70.2%). The table detail includes TLD operators, registration totals, and specific malicious domain metrics.\" width=\"1162\" height=\"954\" class=\"aligncenter\">\n\n<p>I can understand why .bid and .loan are popular with scammers. But why .mobi?! What did I ever do to you, eh?</p>\n\n<p>Who are the scammers registering these through?</p>\n\n<img src=\"https://shkspr.mobi/blog/wp-content/uploads/2026/08/registrars.webp\" alt=\"List of registrars. NameCheap, Gname, Dynadot, NameSilo, GoDaddy.\" width=\"910\" height=\"390\" class=\"aligncenter\">\n\n<p>Ah, our old friends at NameCheap. See <a href=\"https://shkspr.mobi/blog/2021/05/why-do-scammers-love-namecheap/\">Why do scammers love NameCheap?</a></p>\n\n<p>If those five registrars had more effective policies, it might significantly dent the scammers' ability to ply their devious wares. Or they might just move on to other registrars.</p>\n\n<p>As the report points out:</p>\n\n<blockquote><p>suspension rates for blocklisted domains were 7.4% to 16.3%.</p></blockquote>\n\n<p><a href=\"https://interisle.net/s/FullReport_MaliciousRegistrationsintheDomainNameMarket_2026_rev.pdf\">The full report is on the Interisle website</a>.</p>\n\n<h2 id=\"what-can-be-done\"><a href=\"https://shkspr.mobi/blog/2026/09/the-purpose-of-dns-is-to-spread-scams/#what-can-be-done\">What can be done?</a></h2>\n\n<p>I don't know.</p>\n\n<p>In the first instance, it might make sense for registrars to do strong Know Your Customer (KYC) checks on anyone buying a domain. But that stops anyone who wants to anonymously register <code>I-Hate-Nintendo.whatever</code> without risking the wrath of Intellectual Property lawyers.</p>\n\n<p>Also, criminals have access to stolen money and stolen cards. They can convince a hapless mule to register a domain on the criminals' behalf.</p>\n\n<p>Registrars could ask for an escrow payment. Pay €9 for the domain name put €900 in escrow. If your domain appears on a blocklist within the year, you forfeit the money. Criminals with stolen funds are unlikely to care but it would probably put off lots of people from getting a new domain.</p>\n\n<p>There are various banned words and phrases depending on the TLD. For example, <a href=\"https://shkspr.mobi/blog/2024/07/ss-tld-opening-for-direct-registrations/\">South Sudan</a> has a list of political words which they don't want associated with their .ss ccTLD.</p>\n\n<p>But if one gTLD bans a word, a different one might not. A scammer doesn't care if the gTLD is .arse or .elbow - they just want the start of the domain to look legitimate.</p>\n\n<p>Some registrars have strings that they don't allow. In fairness to NameCheap, when I tried to register <code>dwp-payments-gov-uk.pizza</code> it told me that domain was banned. It wouldn't let me get any gTLD with that name.</p>\n\n<p>But all it takes is one registrar to be slightly lax and the scammers get through. Increasing the complexity of the rules is also a hell of a burden on smaller registrars.</p>\n\n<p>Besides, it's pretty easy to get a generic enough looking domain and stick the confusing bit on a subdomain. Here are a clutch mentioned in the report:</p>\n\n<ul>\n<li><code>https://gov.uk-dwpaph.bond/uk/</code></li>\n<li><code>https://gov.uk-dwpcjh.bond/uk/</code></li>\n<li><code>https://gov.uk-dwpclc.bond/uk</code></li>\n<li><code>https://gov.uk-dwpclw.bond/uk</code></li>\n<li><code>https://gov.uk-dwpclj.bond/uk/</code></li>\n</ul>\n\n<p>Perhaps there ought to be a delay before a new domain goes live to allow people to object to it? That would give governments, banks, delivery companies, and a dozen more \"important\" organisations a right to veto any \"dodgy\" looking domain.</p>\n\n<p>But suppose someone wants to register <code>gov-uk-stole-my-horse.horse</code> to protest the government's cruel policy of stealing horses - is that a legitimate use of a domain? What if the Darwin Pensioner Divas - a group of elderly singers - want to take payments for their new album of goth/punk covers, can the DPD delivery company veto <code>dpd-payments.music</code>?</p>\n\n<p>Do we want a domain name system where powerful companies control exactly which domains we can register? If I have an idea for a domain on a Friday night do I have to wait until Monday before it can be launched? Are those companies realistically able to parse millions of domains per year and have a low false-positive rate?</p>\n\n<p>All of these things are possible - but all of them come with an impact on legitimate users. To be clear, I don't know what the right answer is.</p>\n\n<h2 id=\"what-is-icann-doing-about-it\"><a href=\"https://shkspr.mobi/blog/2026/09/the-purpose-of-dns-is-to-spread-scams/#what-is-icann-doing-about-it\">What is ICANN doing about it?</a></h2>\n\n<p>Lots! It has been a few years since I've been to an ICANN meeting, but even back then the topic of abuse was high on the agenda. They appear to be looking at ways to coordinate abuse reports between various entities, along with some other policies which should hopefully work.</p>\n\n<p>There are two salient points from <a href=\"https://hosted-files.sched.co/icann86/b3/TRANSC_I86SQV_Mon08June2026__GNSO-DNS%20Abuse%20Mitigation%20PDP%201%20%281%20of%204%29-en.pdf\">one of the discussions held at the recent meeting</a></p>\n\n<blockquote><p>If anybody thinks that in our current age of AI and as we move into different kinds of computing, DNS abuse is going to numerically stay steady and we will have a downward effect on that baseline 2027 number. I'm not sure that that's an accurate assumption. I think it's going to be the other thing, which is […] it's going to be easier to abuse the DNS.</p></blockquote>\n\n<p>And</p>\n\n<blockquote><p>Abusers are going to abuse because it's just too lucrative, because no matter what we do, they will find the way to make profit off of that, and will try to circumvent everything that we do. That is not a reason not to do it, though.</p></blockquote>\n\n<p>Quite!</p>\n\n<p>As I said, I don't know the answer to this. What I do know is, much like <a href=\"https://shkspr.mobi/blog/2025/08/is-it-possible-to-allow-sideloading-and-keep-users-safe/\">Android's app ecosystem being a haven for scammers</a>, DNS is facing a crisis. When trust in a system goes, only chaos follows.</p>\n\n<p>I don't want to live in a world where I have to show my passport and pay thousands of pounds to register a domain which is only available after being vetted by private interests. But I also don't want to live in a world where scammers have effectively no deterrent from abusing millions of people.</p>\n\n<p>The purpose of a system is what it does. I hope DNS's purpose can become less dangerous while still remaining open.</p>\n<img src=\"https://shkspr.mobi/blog/wp-content/themes/edent-wordpress-theme/info/okgo.php?ID=74588&HTTP_REFERER=Atom\" alt width=\"1\" height=\"1\" loading=\"eager\">",
      "image": null,
      "media": [],
      "authors": [
        {
          "name": "Terence Eden",
          "email": null,
          "url": "https://edent.tel/"
        }
      ],
      "categories": [
        {
          "label": "ICANN",
          "term": "ICANN",
          "url": "https://shkspr.mobi/blog"
        },
        {
          "label": "internet",
          "term": "internet",
          "url": "https://shkspr.mobi/blog"
        },
        {
          "label": "scam",
          "term": "scam",
          "url": "https://shkspr.mobi/blog"
        },
        {
          "label": "spam",
          "term": "spam",
          "url": "https://shkspr.mobi/blog"
        },
        {
          "label": "tld",
          "term": "tld",
          "url": "https://shkspr.mobi/blog"
        },
        {
          "label": "web",
          "term": "web",
          "url": "https://shkspr.mobi/blog"
        }
      ]
    },
    {
      "id": "https://shkspr.mobi/blog/?p=74686",
      "title": "Book Review: The Passing of the Dragon and Other Stories by Ken Liu ★★★★☆",
      "description": "This is a gorgeous set of short stories - and a good deal more accessible than some of the heavyweight prose Liu has previously been involved with. Some of the stories contain sentences which are complex jewels to be savoured.  What I particularly like is the way he moves between almost-prosaic Earth-bound stories to the the most extraordinary flights of fancy. One story might be set in a…",
      "url": "https://shkspr.mobi/blog/2026/09/book-review-the-passing-of-the-dragon-and-other-stories-by-ken-liu/",
      "published": "2026-09-05T11:34:47.000Z",
      "updated": "2026-09-25T21:52:39.000Z",
      "content": "<img src=\"https://shkspr.mobi/blog/wp-content/uploads/2026/09/9781035929306.webp\" alt=\"Book cover.\" width=\"200\" class=\"alignleft\">\n\n<p>This is a gorgeous set of short stories - and a good deal more accessible than some of the heavyweight prose Liu has previously been involved with. Some of the stories contain sentences which are complex jewels to be savoured.</p>\n\n<p>What I particularly like is the way he moves between almost-prosaic Earth-bound stories to the the most extraordinary flights of fancy. One story might be set in a downtown art gallery, the next in the ice-rings of a far-off planet. The creeping feeling of senescence haunts the reader as they flit from story to story.</p>\n\n<p>Much like his full-length novel <a href=\"https://shkspr.mobi/blog/2025/09/book-review-all-that-we-see-or-seem-by-ken-liu/\">All That We See or Seem</a>, Liu has an incredible knack for tapping in to modern fears and weaving tall tales around them. There's a tenderness in all his character - even when a couple of the stories go nowhere, it is still pleasant to spend time in the worlds he has created.</p>\n\n<p>It is, perhaps, missing a cohesive theme - the dragons come and go throughout the stories. Nevertheless, a compelling work chock full of fantastical ideas.</p>\n\n<p>If you're in the mood for a wide and varied selection of stories, this is well worth picking up.</p>\n\n<p>Many thanks to NetGalley for the review copy. Passing of the Dragon is available to buy now.</p>\n<img src=\"https://shkspr.mobi/blog/wp-content/themes/edent-wordpress-theme/info/okgo.php?ID=74686&HTTP_REFERER=Atom\" alt width=\"1\" height=\"1\" loading=\"eager\">",
      "image": null,
      "media": [],
      "authors": [
        {
          "name": "Terence Eden",
          "email": null,
          "url": "https://edent.tel/"
        }
      ],
      "categories": [
        {
          "label": "Book Review",
          "term": "Book Review",
          "url": "https://shkspr.mobi/blog"
        },
        {
          "label": "NetGalley",
          "term": "NetGalley",
          "url": "https://shkspr.mobi/blog"
        },
        {
          "label": "Sci Fi",
          "term": "Sci Fi",
          "url": "https://shkspr.mobi/blog"
        }
      ]
    },
    {
      "id": "https://shkspr.mobi/blog/?p=74429",
      "title": "A reasonably practical guide to validating RFC 9421 HTTP Signatures for ActivityPub in PHP",
      "description": "If you're reading this, you've probably been hitting your head against a brick wall trying to parse and decipher the new HTTP Signatures sent by Mastodon and other Fediverse servers.  This is a basic and somewhat incomplete guide to accepting these signatures. I'm sure there are various gotchas, but it works with the signatures I've seen in the wild.  Shut Up And Show Me The Code!  OK, wow, no…",
      "url": "https://shkspr.mobi/blog/2026/09/a-reasonably-practical-guide-to-validating-rfc-9421-http-signatures-for-activitypub-in-php/",
      "published": "2026-09-03T11:34:12.000Z",
      "updated": "2026-09-04T13:36:29.000Z",
      "content": "<p>If you're reading this, you've probably been hitting your head against a brick wall trying to parse and decipher the new HTTP Signatures sent by Mastodon and other Fediverse servers.</p>\n\n<p>This is a basic and somewhat incomplete guide to accepting these signatures. I'm sure there are various gotchas, but it works with the signatures I've seen in the wild.</p>\n\n<h2 id=\"shut-up-and-show-me-the-code\"><a href=\"https://shkspr.mobi/blog/2026/09/a-reasonably-practical-guide-to-validating-rfc-9421-http-signatures-for-activitypub-in-php/#shut-up-and-show-me-the-code\">Shut Up And Show Me The Code!</a></h2>\n\n<p>OK, wow, no need to be a dick about it! Here's how I validated a real signature that my server received. This requires PHP 8.4 or newer.</p>\n\n<pre><code class=\"language-php\">$verified = openssl_verify(\n    data:       '\"@method\": POST\n\"@target-uri\": https://example.viii.fi/inbox\n\"content-digest\": sha-256=:tFdB/ENGczHMlZMDb66pXoUi2d0OqH2iBHdnN/WV1mc=:\n\"@signature-params\": (\"@method\" \"@target-uri\" \"content-digest\");created=1787780262;keyid=\"https://mastodon.social/users/Edent#main-key\"',\n    signature:  base64_decode( \"sIfmNsM/Q8iG6AJlne1IkZVjQSVFDEYIPsnoSOXQY+W3Eb4+SOn9o4J5SQmFOP+Jecjf3ioFwUdsrFjAGkUUOHPvSbNWkGKtNuGm+C6r3aI3JBCFGPqX3ITgZYV76CF7JJJ5hPGaG8YH/XdmxVIeFfD3M39FQCncMyyq7xJJvwKKP1mzS5s1vNQie8hbQ9owRjtqvoWcmM9GEYCUHNcMPLjZc+CBrj8sfBbNTYgIFI4UtirOaRJvYymxXjmXuzeVYxQujMjAjgobxQ8QFv0zlYsHk+gS5EYyafpJG9zmfCFSoF9+ZwqKNADmuADbISD9LZIH/bmkPoNXhxaeFPqYog==\" ),\n    public_key: \"-----BEGIN PUBLIC KEY-----\\nMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAsYMEs4waqk/6gaS+xn1T\\nYygElTtNIFNkBcEdEBMaeoGVhyZiVKtSjJCS4z+X+394PKvcfSTcFILIt2GI2jOB\\nHD0M2fFgxc8mmdSdCQkgEh9jF3bFI3kopDvzYf726iioYKlHXKpfPKvFt7EJgKH7\\naCtS25NQkek3YUd6y3VBcT3R6Xhze9P3QNoZMIsFXklgXDKj+EllfbUqLf1vxt3s\\nmD9ETxy2bJi9FheE0uY2WhARn49XAvwczM5Wzt+zqxVEtgpi5v2+ZZAVKhDnJkiC\\nCCuI6hrSnKNIx/5mSlX0a0S5h5d03djrCkYsqmwelu01rhOXP2grsz4BXp0y2wrO\\n3QIDAQAB\\n-----END PUBLIC KEY-----\\n\",\n    algorithm:  \"sha256\"\n);\n\necho $verified;\n</code></pre>\n\n<p>Copy and paste that into PHP and you should see that <code>$verified</code> is true.</p>\n\n<h2 id=\"now-explain-the-code\"><a href=\"https://shkspr.mobi/blog/2026/09/a-reasonably-practical-guide-to-validating-rfc-9421-http-signatures-for-activitypub-in-php/#now-explain-the-code\">NOW EXPLAIN THE CODE</a></h2>\n\n<p>Say please.</p>\n\n<h2 id=\"please\"><a href=\"https://shkspr.mobi/blog/2026/09/a-reasonably-practical-guide-to-validating-rfc-9421-http-signatures-for-activitypub-in-php/#please\">PLEASE!!!</a></h2>\n\n<p>Along with the message sent to your server, you will have received HTTP headers like this:</p>\n\n<pre><code class=\"language-_\">content-digest: sha-256=:tFdB/ENGczHMlZMDb66pXoUi2d0OqH2iBHdnN/WV1mc=:\nsignature: sig1=:sIfmNsM/Q8iG6AJlne1IkZVjQSVFDEYIPsnoSOXQY+W3Eb4+SOn9o4J5SQmFOP+Jecjf3ioFwUdsrFjAGkUUOHPvSbNWkGKtNuGm+C6r3aI3JBCFGPqX3ITgZYV76CF7JJJ5hPGaG8YH/XdmxVIeFfD3M39FQCncMyyq7xJJvwKKP1mzS5s1vNQie8hbQ9owRjtqvoWcmM9GEYCUHNcMPLjZc+CBrj8sfBbNTYgIFI4UtirOaRJvYymxXjmXuzeVYxQujMjAjgobxQ8QFv0zlYsHk+gS5EYyafpJG9zmfCFSoF9+ZwqKNADmuADbISD9LZIH/bmkPoNXhxaeFPqYog==:\nsignature-input: sig1=(\"@method\" \"@target-uri\" \"content-digest\");created=1787780262;keyid=\"https://mastodon.social/users/Edent#main-key\"\n</code></pre>\n\n<p>The <code>signature-input</code> tells you how to construct a \"Signature Base\". You have to build a text string which places the various components in the order specified and separated with a newline:</p>\n\n<pre><code class=\"language-_\">\"@method\": POST\n\"@target-uri\": https://example.viii.fi/inbox\n\"content-digest\": sha-256=:tFdB/ENGczHMlZMDb66pXoUi2d0OqH2iBHdnN/WV1mc=:\n\"@signature-params\": (\"@method\" \"@target-uri\" \"content-digest\");created=1787780262;keyid=\"https://mastodon.social/users/Edent#main-key\"\n</code></pre>\n\n<p>Where <code>@method</code> is the HTTP method used to send data to your server (usually <code>GET</code> or <code>POST</code>), and <code>@target-uri</code> is the URl the message was sent to (usually your inbox).</p>\n\n<p>The <code>publicKey</code> is slightly trickier. As you can see, the <code>signature-input</code> ends with <code>keyid=\"https://mastodon.social/users/Edent#main-key</code></p>\n\n<p>If you make a signed request to that URl, you'll get back an ActivityPub Actor document. It will look something like this:</p>\n\n<pre><code class=\"language-json\">{\n  \"@context\": [\n    \"https://www.w3.org/ns/activitystreams\",\n    \"https://w3id.org/security/v1\",\n  ],\n  \"id\": \"https://mastodon.social/users/Edent\",\n  \"webfinger\": \"Edent@mastodon.social\",\n  \"type\": \"Person\",\n  \"name\": \"Terence Eden\",\n  \"publicKey\": {\n    \"id\": \"https://mastodon.social/users/Edent#main-key\",\n    \"owner\": \"https://mastodon.social/users/Edent\",\n    \"publicKeyPem\": \"-----BEGIN PUBLIC KEY-----\\nMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAsYMEs4waqk/6gaS+xn1T\\nYygElTtNIFNkBcEdEBMaeoGVhyZiVKtSjJCS4z+X+394PKvcfSTcFILIt2GI2jOB\\nHD0M2fFgxc8mmdSdCQkgEh9jF3bFI3kopDvzYf726iioYKlHXKpfPKvFt7EJgKH7\\naCtS25NQkek3YUd6y3VBcT3R6Xhze9P3QNoZMIsFXklgXDKj+EllfbUqLf1vxt3s\\nmD9ETxy2bJi9FheE0uY2WhARn49XAvwczM5Wzt+zqxVEtgpi5v2+ZZAVKhDnJkiC\\nCCuI6hrSnKNIx/5mSlX0a0S5h5d03djrCkYsqmwelu01rhOXP2grsz4BXp0y2wrO\\n3QIDAQAB\\n-----END PUBLIC KEY-----\\n\"\n  },\n</code></pre>\n\n<p>The <code>publicKeyPem</code> is the string you need. There's no need to convert the <code>\\n</code> to literal newlines.</p>\n\n<h2 id=\"is-that-it\"><a href=\"https://shkspr.mobi/blog/2026/09/a-reasonably-practical-guide-to-validating-rfc-9421-http-signatures-for-activitypub-in-php/#is-that-it\">Is that it?</a></h2>\n\n<p>Not quite! All we've done so far is verify the headers. It is possible that these are genuine headers but attached to a fraudulent body.</p>\n\n<p>This takes us back to the header <code>\"content-digest\": sha-256=:tFdB/ENGczHMlZMDb66pXoUi2d0OqH2iBHdnN/WV1mc=:</code></p>\n\n<p>That says that the body of the message sent has a Base64 encoded SHA256 hash of <code>tFdB/ENGczHMlZMDb66pXoUi2d0OqH2iBHdnN/WV1mc=</code>.</p>\n\n<p>To calculate your own content digest in PHP:</p>\n\n<pre><code class=\"language-php\">$input = file_get_contents( \"php://input\" );\n$digestCalculated = base64_encode(\n    hash(\n        algo: \"sha256\",\n        data: $input,\n        binary: true\n    )\n);\n</code></pre>\n\n<p>Does your digest match the one sent along with the headers? If not, something dodgy is going on.</p>\n\n<h2 id=\"putting-it-all-together\"><a href=\"https://shkspr.mobi/blog/2026/09/a-reasonably-practical-guide-to-validating-rfc-9421-http-signatures-for-activitypub-in-php/#putting-it-all-together\">Putting it all together</a></h2>\n\n<p>The steps are:</p>\n\n<ol>\n<li>Get the headers.</li>\n<li>Get the body.</li>\n<li>From the headers' <code>content-digest</code> extract the algorithm and hash.</li>\n<li>Using the body, calculate your own hash using the algorithm from <code>content-digest</code>.</li>\n<li>Does your hash match the sent hash? If not, stop. If so, proceed.</li>\n<li>From the headers' <code>signature</code> extract the base64 encoded signature.</li>\n<li>From the headers' <code>signature-input</code> extract the signature-input string.</li>\n<li>From the signature-input string extract the order of the Signature Base.</li>\n<li>Construct the Signature Base.</li>\n<li>From the signature-input string extract the keyid.</li>\n<li>Get the Public Key from the keyid.</li>\n<li>Use <code>openssl_verify()</code> to verify the Signature Base and the base64 decoded signature, against the Public Key using SHA256.</li>\n</ol>\n\n<p>Note, <a href=\"https://docs.joinmastodon.org/spec/security/#http-message-signatures\">Mastodon <em>only</em> uses SHA256</a>.  I think it should explicitly say which algorithm it is using <a href=\"https://github.com/mastodon/mastodon/issues/29905#issuecomment-5440336919\">and have raised the issue</a>.</p>\n\n<h3 id=\"in-code-form\"><a href=\"https://shkspr.mobi/blog/2026/09/a-reasonably-practical-guide-to-validating-rfc-9421-http-signatures-for-activitypub-in-php/#in-code-form\">In Code Form</a></h3>\n\n<p>This is how you do it in PHP. Please read this carefully as there are some hard-coded assumptions.</p>\n\n<pre><code class=\"language-php\"><?php\n\n//  Validate the Digest.\n//  It is the hash of the raw input string, in binary, encoded as base64.\n\n//  The format is content-digest => <algorithm>=:<base64 encoded hash>:\n$digestString = $headers[\"content-digest\"];\n//  The Base64 encoding may have multiple `=` at the end. So split this at the first `=`.\n$digestData = explode( separator: \"=\", string: $digestString, limit: 2 );\n\n//  Hashes are in lowercase, but have a `-` in their name.\n//  This is not what hash_algos() expects.\n$digestAlgorithm = str_replace( search: \"-\", replace: \"\", subject: $digestData[0] );\n\n//  The hash is surrounded by `:` characters.\n$digestHash = str_replace( search: \":\", replace: \"\", subject: $digestData[1] );\n\n//  Check if the hash algorithm is one known about to PHP.\n//  If not, reject and record an error.\nif ( !in_array( needle:$digestAlgorithm, haystack: hash_algos() ) ) {\n    return false;\n}\n\n//  Manually calculate the digest based on the data sent.\n$digestCalculated = base64_encode( hash( algo: $digestAlgorithm, data: $input, binary: true ) );\n\n//  Does our calculation match what was sent?\nif ( !( $digestCalculated == $digestHash ) ) {\n    return false;\n}\n\n//  The signature format is signature => <signature name>=:<base64 encoded hash>:\n$signatureString = $headers[\"signature\"];\n//  The Base64 encoding may have multiple `=` at the end. So split this at the first `=`.\n$signatureData = explode( separator: \"=\", string: $signatureString, limit: 2 );\n$signatureName = $signatureData[0];\n\n//  The signature is surrounded by `:` characters.\n$signatureB64 = str_replace( search: \":\", replace: \"\", subject: $signatureData[1] );\n\n//  The signature-input format is complicated!\n$signatureInputString = $headers[\"signature-input\"];\n\n//  Get the parameters. Assume there is only one signature.\n$signatureParamsString = explode( separator: \"=\", string: $signatureInputString, limit: 2 )[1];\n\n//  Get the different elements of the signature.\n$signatureInputData = explode( separator: \";\", string: $signatureInputString );\n\n//  Construct the data.\n$signatureInput = [];\nforeach( $signatureInputData as $signatureInputParts ) {\n    $partsData = explode( separator: \"=\", string: $signatureInputParts );\n    //  Strip quotes from keyid and parentheses from sig1.\n    if ( \"keyid\" == $partsData[0] ) {\n        $partsData[1] = str_replace( search: \"\\\"\", replace: \"\", subject: $partsData[1] );\n    }\n\n    if ( $signatureName == $partsData[0] ) {\n        $partsData[1] = str_replace( search: [\"(\", \")\"], replace: \"\", subject: $partsData[1] );\n    }\n\n    $signatureInput[ $partsData[0] ] = $partsData[1] ;\n}\n\n$signatureStructure = $signatureInput[$signatureName];\n$signatureKeyID     = $signatureInput[\"keyid\"];\n\n//  Remove quotes.\n$signatureStructure = str_replace( search: \"\\\"\", replace: \"\", subject: $signatureStructure );\n$signatureStructureData = explode( separator: \" \", string: $signatureStructure );\n\n//  https://www.rfc-editor.org/info/rfc9421/#section-2.5\n$signatureBase = \"\";\nforeach ( $signatureStructureData as $signatureStructureParts ) {\n    if ( \"@method\" == $signatureStructureParts ) {\n        //  https://www.rfc-editor.org/info/rfc9421/#name-method\n        $signatureBase .= \"\\\"@method\\\": \" . $_SERVER[\"REQUEST_METHOD\"] . \"\\n\";\n    }\n    if ( \"@target-uri\" == $signatureStructureParts ) {\n        //  https://www.rfc-editor.org/info/rfc9421/#section-2.2.2\n        //  Change the domain name to your own.\n        $signatureBase .= \"\\\"@target-uri\\\": https://EXAMPLE.COM\" . $_SERVER[\"REQUEST_URI\"] . \"\\n\";\n    }\n    if ( \"content-digest\" == $signatureStructureParts ) {\n        $signatureBase .= \"\\\"content-digest\\\": $digestString\\n\";\n    }\n}\n\n//  https://victoronsoftware.com/posts/http-message-signatures/#how-the-signature-is-created\n$signatureBase .= \"\\\"@signature-params\\\": $signatureParamsString\";\n\n//  Get the signing user's public key.\n//  This is usually in the form `https://example.com/user/username#main-key`\n//  This is to differentiate if the user has multiple keys.\n//  This may need to be a signed request. You will need to write your own getDataFromURl() function to get the sending user's key.\n$userData  = getDataFromURl( $signatureKeyID );\n$publicKey = $userData[\"publicKey\"][\"publicKeyPem\"];\n\n//  Verify the request\n$verified = openssl_verify(\n    data:       $signatureBase,\n    signature:  base64_decode( $signatureB64 ),\n    public_key: $publicKey,\n    algorithm:  $digestAlgorithm\n);\n\n//  Convert the result to boolean.\nif ( $verified === 1 ) {\n    $verified = true;\n} elseif ( $verified === 0 ) {\n    $verified = false;\n} else {\n    $verified = null;\n}\n\nreturn $verified;\n</code></pre>\n\n<h2 id=\"further-reading\"><a href=\"https://shkspr.mobi/blog/2026/09/a-reasonably-practical-guide-to-validating-rfc-9421-http-signatures-for-activitypub-in-php/#further-reading\">Further Reading</a></h2>\n\n<ul>\n<li><a href=\"https://www.rfc-editor.org/info/rfc9421/\">RFC 9421 HTTP Message Signatures</a></li>\n<li><a href=\"https://victoronsoftware.com/posts/http-message-signatures/\">Understanding HTTP message signatures: A developer's guide</a></li>\n<li><a href=\"https://www.otoroshi.io/docs/tutorials/http-message-signatures-rfc9421/\">Sign and verify HTTP messages (RFC 9421)</a></li>\n<li><a href=\"https://darutk.medium.com/verification-of-http-message-signatures-501bbdc7dfec\">Verification of HTTP Message Signatures</a></li>\n<li><a href=\"https://github.com/macgirvin/HTTP-Message-Signer\">HTTP-Message-Signer in PHP</a></li>\n</ul>\n\n<h2 id=\"thanks-to-nlnet\"><a href=\"https://shkspr.mobi/blog/2026/09/a-reasonably-practical-guide-to-validating-rfc-9421-http-signatures-for-activitypub-in-php/#thanks-to-nlnet\">Thanks to NLnet</a></h2>\n\n<p>This blog post was funded in part by the work I'm doing for my NLnet NGI0 grant. Thanks!</p>\n\n<p><a href=\"https://nlnet.nl/project/ActivityBot/\"><img src=\"https://shkspr.mobi/blog/wp-content/uploads/2026/08/NGI-logos.webp\" alt=\"NLnet logo.\" width=\"900\" height=\"200\" class=\"aligncenter\"></a></p>\n<img src=\"https://shkspr.mobi/blog/wp-content/themes/edent-wordpress-theme/info/okgo.php?ID=74429&HTTP_REFERER=Atom\" alt width=\"1\" height=\"1\" loading=\"eager\">",
      "image": null,
      "media": [],
      "authors": [
        {
          "name": "Terence Eden",
          "email": null,
          "url": "https://edent.tel/"
        }
      ],
      "categories": [
        {
          "label": "ActivityBot",
          "term": "ActivityBot",
          "url": "https://shkspr.mobi/blog"
        },
        {
          "label": "ActivityPub",
          "term": "ActivityPub",
          "url": "https://shkspr.mobi/blog"
        },
        {
          "label": "mastodon",
          "term": "mastodon",
          "url": "https://shkspr.mobi/blog"
        },
        {
          "label": "php",
          "term": "php",
          "url": "https://shkspr.mobi/blog"
        },
        {
          "label": "webdev",
          "term": "webdev",
          "url": "https://shkspr.mobi/blog"
        }
      ]
    }
  ]
}