geeky

The Cursed Computer Iceberg Meme

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Blackle Mori

More awesome from Blackle Mori, whose praises I sung recently over The Basilisk Collection. This time we’re treated to a curated list of 182 articles demonstrating the “peculiarities and weirdness” of computers. Starting from relatively well-known memes like little Bobby Tables, the year 2038 problem, and how all web browsers pretend to be each other, we descend through the fast inverse square root (made famous by Quake III), falsehoods programmers believe about time (personally I’m more of a fan of …names, but then you might expect that), the EICAR test file, the “thank you for playing Wing Commander” EMM386 in-memory hack, The Basilisk Collection itself, and the GIF MD5 hashquine (which I’ve shared previously) before eventually reaching the esoteric depths of posuto and the nightmare that is Japanese postcodes…

Plus many, many things that were new to me and that I’ve loved learning about these last few days.

It’s definitely not a competition; it’s a learning opportunity wrapped up in the weirdest bits of the field. Have an explore and feed your inner computer science geek.

**

Despite the fact that it’s existed for 11 years, TIL about globstar in Bash. Set shopt -s globstar and ** globs become fully recursive, making that bulk transcode operation much simpler. 🤯

HTML Movies

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1. a (1998)

Documentary about the Buddhist sect responsible for the 1995 Tokyo subway Sarin gas attack.

2. body (2003)

Also known as Jism. No, really. A tale of passion and murder featuring an alcoholic lawyer and the wife of a travelling millionaire.

3. canvas (1992)

Gary Busey stars as an artist who takes part in a heist to save his brother from murderous art thieves.

…

Matt Round

We could have had so many HTML-themed Troma Nights, if we’d wanted…

A long while ago, inspired by Nick Berry‘s analysis of optimal Hangman strategy, I worked it backwards to find the hardest words to guess when playing Hangman. This week, I showed these to my colleague Grace – who turns out to be a fan of word puzzles – and our conversation inspired me to go a little deeper. Is it possible, I thought, for me to make a Hangman game that cheats by changing the word it’s thinking of based on the guesses you make in order to make it as difficult as possible for you to win?

Play “Cheating Hangman”

The principle is this: every time the player picks a letter, but before declaring whether or not it’s found in the word –

Make a list of all possible words that would fit into the boxes from the current game state.
If there are lots of them, still, that’s fine: let the player’s guess go ahead.
But if the player’s managing to narrow down the possibilities, attempt to change the word that they’re trying to guess! The new word must be:
- Legitimate: it must still be the same length, have correctly-guessed letters in the same places, and contain no letters that have been declared to be incorrect guesses.
- Harder: after resolving the player’s current guess, the number of possible words must be larger than the number of possible words that would have resulted otherwise.

You might think that this strategy would just involve changing the target word so that you can say “nope” to the player’s current guess. That happens a lot, but it’s not always the case: sometimes, it’ll mean changing to a different word in which the guessed letter also appears. Occasionally, it can even involve changing from a word in which the guessed letter didn’t appear to one in which it does: that is, giving the player a “freebie”. This may seem counterintuitive as a strategy, but it sometimes makes sense: if saying “yeah, there’s an E at the end” increases the number of possible words that it might be compared to saying “no, there are no Es” then this is the right move for a cheating hangman.

Playing against a cheating hangman also lends itself to devising new strategies as a player, too, although I haven’t yet looked deeply into this. But logically, it seems that the optimal strategy against a cheating hangman might involve making guesses that force the hangman to bisect the search space: knowing that they’re always going to adapt towards the largest set of candidate words, a perfect player might be able to make guesses to narrow down the possibilities as fast as possible, early on, only making guesses that they actually expect to be in the word later (before their guess limit runs out!).

I also find myself wondering how easily I could adapt this into a “helpful hangman”: a game which would always change the word that you’re trying to guess in order to try to make you win. This raises the possibility of a whole new game, “suicide hangman”, in which the player is trying to get themselves killed and so is trying to pick letters that can’t possibly be in the word and the hangman is trying to pick words in which those letters can be found, except where doing so makes it obvious which letters the player must avoid next. Maybe another day.

In the meantime, you’re welcome to go play the game (and let me know what you think, below!) and, if you’re of such an inclination, read the source code. I’ve used some seriously ugly techniques to make this work, including regular expression metaprogramming (using regular expressions to write regular expressions), but the code should broadly make sense if you want to adapt it. Have fun!

Play “Cheating Hangman”

Update 26 September 2019, 16:23: I’ve now added “helpful mode”, where the computer tries to cheat on your behalf rather than against you, but it’s not as helpful as you’d think because it assumes you’re playing optimally and have already memorised the dictionary!

Update 1 October 2019, 06:40: Now featured on MetaFilter; hi, MeFites!

css-only-chat/README.md at master · kkuchta/css-only-chat · GitHub

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CSS-Only Chat

A truly monstrous async web chat using no JS whatsoever on the frontend.

Wait what

This is an asynchronous chat that sends + receives messages in the browser with no reloads and no javascript.

Ok so how

Background-images loaded via pseudoselectors + a forever-loading index page (remember Comet?).

Say that again?

Ok, so there are two things we need the browser to do: send data and receive data. Let’s start with the first.

Sending Data

CSS is really limited in what it can do. However, we can use it to effectively detect button presses:
.some-button:active {
  background-image: url('some_image.jpg')
}
What’s cool is that a browser won’t actually load that background image until this selector is used – that is, when this button is pressed. So now we have a way to trigger a request to a server of our choice on a button press. That sounds like data sending!

Now, of course, this only works once per button (since a browser won’t try to load that image twice), but it’s a start.

Receiving Data

Since we can’t use JS, it’s really hard to change a page after it’s already been loaded. But it is possible.

Back before websockets were widely supported, we had to use clever hacks if we wanted to push data from a server to a client in an ongoing basis. One such hack was just to make the page never finish loading. It turns out that you can tell the browser to start rendering a page before it’s finished loading (using the Transfer-Encoding: chunked http header). And when you do that, you don’t actually have to stop loading the page. You can just keep adding stuff to the bottom of the html forever, at whatever rate you want.

So, for example, you could start sending a normal html page, then just stop sending html (while still telling the client you’re sending) until you’re ready to deliver another message.

Now, all this lets us do is periodically append html to the page. What can we do with that? How about, when you load the index page, this happens:

We load up the first pile of html we want to show. A welcome message, etc.

We stop loading html for a while until we want to send some sort of update.

Now we load up a <style> element that display: none‘s all the previous html

Then we load up whatever new html we want to show

Finally we wait until the next update we want to send and GOTO 3.

Single-use buttons?

Ok, so we have that problem earlier where each button is only single-use. It tries to send a get request once, then never will again.

Thankfully, our method of receiving data fixes that for us. Here’s what happens:

We show an “a” button whose background image is like “img/a”.

When you press it, the server receives the image request for “a”

The server then pushes an update to the client to hide the current button and replace it with one whose background images is “image/aa”.

If the buttons you pressed were “h”, “e”, and “l”, then the “a” button’s background image url would be “img/hela”. And since we’re replacing all buttons every time you press one, the single-use button problem goes away!

Misc other details

We actually encode a bit more info into the button urls (like each client’s id)

Because the data-sending and data-receiving happens on different threads, we need inter-thread communication. That sounds like work, so we’ll just use Redis pubsub for that.

FAQ

What inspired this? Chernobyl, Hindenburg, The Tacoma Narrows Bridge…

Really? No, it was this clever tweet by davywtf.

Why’s your code suck Why do you suck?

No but really Because I was mostly making this up as I went. There’s a lot of exploratory coding here that I only minimally cleaned up. If I rebuilt it I’d store the UI state for a client in redis and just push it out in its entirety when needed via a single generic screen-updating mechanism.

What could go wrong with this technique? Broken by browser bg-image handling changes; long-request timeouts; running out of threads; fast-clicking bugs; generic concurrency headaches; poor handling by proxies; it’s crazy inaccessible; etc etc

Should I use this in real life? Dear god yes.

I have an idea for how this could be made better/worse/hackier Tweet at me (@kkuchta). I’m always down to see a terrible idea taken further!

Practical Details

If you want to install and use this locally you should:

Re-evaluate your life choices

If you simply must continue, check out INSTALL.md

If you want to contribute, see number 1 above. After that, just fork this repo, make a change, and then open a PR against this repo.
Kevin Kuchta (GitHub)

A poem about Silicon Valley, assembled from Quora questions about Silicon Valley

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Why do so many startups fail?
Why are all the hosts on CouchSurfing male?
Are we going to be tweeting for the rest of our lives?
Why do Silicon Valley billionaires choose average-looking wives?

What makes a startup ecosystem thrive?
What do people plan to do once they’re over 35?
Is an income of $160K enough to survive?
What kind of car does Mark Zuckerberg drive?

…

Jason O. Gilbert (Splinter News)

Enigma, the Bombe, and Typex

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How to guides

How to encrypt/decrypt with Enigma

We’ll start with a step-by-step guide to decrypting a known message. You can see the result of these steps in CyberChef here. Let’s say that our message is as follows:

XTSYN WAEUG EZALY NRQIM AMLZX MFUOD AWXLY LZCUZ QOQBQ JLCPK NDDRW F

And that we’ve been told that a German service Enigma is in use with the following settings:

Rotors III, II, and IV, reflector B, ring settings (Ringstellung in German) KNG, plugboard (Steckerbrett)AH CO DE GZ IJ KM LQ NY PS TW, and finally the rotors are set to OPM.

Enigma settings are generally given left-to-right. Therefore, you should ensure the 3-rotor Enigma is selected in the first dropdown menu, and then use the dropdown menus to put rotor III in the 1st rotor slot, II in the 2nd, and IV in the 3rd, and pick B in the reflector slot. In the ring setting and initial value boxes for the 1st rotor, put K and O respectively, N and P in the 2nd, and G and M in the 3rd. Copy the plugboard settings AH CO DE GZ IJ KM LQ NY PS TW into the plugboard box. Finally, paste the message into the input window.

The output window will now read as follows:

HELLO CYBER CHEFU SERST HISIS ATEST MESSA GEFOR THEDO CUMEN TATIO N

The Enigma machine doesn’t support any special characters, so there’s no support for spaces, and by default unsupported characters are removed and output is put into the traditional five-character groups. (You can turn this off by disabling “strict input”.) In some messages you may see X used to represent space.

Encrypting with Enigma is exactly the same as decrypting – if you copy the decrypted message back into the input box with the same recipe, you’ll get the original ciphertext back.

Plugboard, rotor and reflector specifications

The plugboard exchanges pairs of letters, and is specified as a space-separated list of those pairs. For example, with the plugboard AB CD, A will be exchanged for B and vice versa, C for D, and so forth. Letters that aren’t specified are not exchanged, but you can also specify, for example, AA to note that A is not exchanged. A letter cannot be exchanged more than once. In standard late-war German military operating practice, ten pairs were used.

You can enter your own components, rather than using the standard ones. A rotor is an arbitrary mapping between letters – the rotor specification used here is the letters the rotor maps A through Z to, so for example with the rotor ESOVPZJAYQUIRHXLNFTGKDCMWB, A maps to E, B to S, and so forth. Each letter must appear exactly once. Additionally, rotors have a defined step point (the point or points in the rotor’s rotation at which the neighbouring rotor is stepped) – these are specified using a < followed by the letters at which the step happens.

Reflectors, like the plugboard, exchange pairs of letters, so they are entered the same way. However, letters cannot map to themselves.

How to encrypt/decrypt with Typex

The Typex machine is very similar to Enigma. There are a few important differences from a user perspective:

Five rotors are used.

Rotor wirings cores can be inserted into the rotors backwards.

The input plugboard (on models which had one) is more complicated, allowing arbitrary letter mappings, which means it functions like, and is entered like, a rotor.

There was an additional plugboard which allowed rewiring of the reflector: this is supported by simply editing the specified reflector.

Like Enigma, Typex only supports enciphering/deciphering the letters A-Z. However, the keyboard was marked up with a standardised way of representing numbers and symbols using only the letters. You can enable emulation of these keyboard modes in the operation configuration. Note that this needs to know whether the message is being encrypted or decrypted.

How to attack Enigma using the Bombe

Let’s take the message from the first example, and try and decrypt it without knowing the settings in advance. Here’s the message again:

XTSYN WAEUG EZALY NRQIM AMLZX MFUOD AWXLY LZCUZ QOQBQ JLCPK NDDRW F

Let’s assume to start with that we know the rotors used were III, II, and IV, and reflector B, but that we know no other settings. Put the ciphertext in the input window and the Bombe operation in your recipe, and choose the correct rotors and reflector. We need one additional piece of information to attack the message: a “crib”. This is a section of known plaintext for the message. If we know something about what the message is likely to contain, we can guess possible cribs.

We can also eliminate some cribs by using the property that Enigma cannot encipher a letter as itself. For example, let’s say our first guess for a crib is that the message begins with “Hello world”. If we enter HELLO WORLD into the crib box, it will inform us that the crib is invalid, as the W in HELLO WORLD corresponds to a W in the ciphertext. (Note that spaces in the input and crib are ignored – they’re included here for readability.) You can see this in CyberChef here

Let’s try “Hello CyberChef” as a crib instead. If we enter HELLO CYBER CHEF, the operation will run and we’ll be presented with some information about the run, followed by a list of stops. You can see this here. Here you’ll notice that it says Bombe run on menu with 0 loops (2+ desirable)., and there are a large number of stops listed. The menu is built from the crib you’ve entered, and is a web linking ciphertext and plaintext letters. (If you’re maths inclined, this is a graph where letters – plain or ciphertext – are nodes and states of the Enigma machine are edges.) The machine performs better on menus which have loops in them – a letter maps to another to another and eventually returns to the first – and additionally on longer menus. However, menus that are too long risk failing because the Bombe doesn’t simulate the middle rotor stepping, and the longer the menu the more likely this is to have happened. Getting a good menu is a mixture of art and luck, and you may have to try a number of possible cribs before you get one that will produce useful results.

In this case, if we extend our crib by a single character to HELLO CYBER CHEFU, we get a loop in the menu (that U maps to a Y in the ciphertext, the Y in the second cipher block maps to A, the A in the third ciphertext block maps to E, and the E in the second crib block maps back to U). We immediately get a manageable number of results. You can see this here. Each result gives a set of rotor initial values and a set of identified plugboard wirings. Extending the crib further to HELLO CYBER CHEFU SER produces a single result, and it has also recovered eight of the ten plugboard wires and identified four of the six letters which are not wired. You can see this here.

We now have two things left to do:

Recover the remaining plugboard settings.

Recover the ring settings.

This will need to be done manually.

Set up an Enigma operation with these settings. Leave the ring positions set to A for the moment, so from top to bottom we have rotor III at initial value E, rotor II at C, and rotor IV at G, reflector B, and plugboard DE AH BB CO FF GZ LQ NY PS RR TW UU.

You can see this here. You will immediately notice that the output is not the same as the decryption preview from the Bombe operation! Only the first three characters – HEL – decrypt correctly. This is because the middle rotor stepping was ignored by the Bombe. You can correct this by adjusting the ring position and initial value on the right-hand rotor in sync. They are currently A and G respectively. Advance both by one to B and H, and you’ll find that now only the first two characters decrypt correctly.

Keep trying settings until most of the message is legible. You won’t be able to get the whole message correct, but for example at F and L, which you can see here, our message now looks like:

HELLO CYBER CHEFU SERTC HVSJS QTEST KESSA GEFOR THEDO VUKEB TKMZM T

At this point we can recover the remaining plugboard settings. The only letters which are not known in the plugboard are J K V X M I, of which two will be unconnected and two pairs connected. By inspecting the ciphertext and partially decrypted plaintext and trying pairs, we find that connecting IJ and KM results, as you can see here, in:

HELLO CYBER CHEFU SERST HISIS ATEST MESSA GEFOR THEDO CUMEO TMKZK T

This is looking pretty good. We can now fine tune our ring settings. Adjusting the right-hand rotor to G and M gives, as you can see here,

HELLO CYBER CHEFU SERST HISIS ATEST MESSA GEFOR THEDO CUMEN WMKZK T

which is the best we can get with only adjustments to the first rotor. You now need to adjust the second rotor. Here, you’ll find that anything from D and F to Z and B gives the correct decryption, for example here. It’s not possible to determine the exact original settings from only this message. In practice, for the real Enigma and real Bombe, this step was achieved via methods that exploited the Enigma network operating procedures, but this is beyond the scope of this document.

What if I don’t know the rotors?

You’ll need the “Multiple Bombe” operation for this. You can define a set of rotors to choose from – the standard WW2 German military Enigma configurations are provided or you can define your own – and it’ll run the Bombe against every possible combination. This will take up to a few hours for an attack against every possible configuration of the four-rotor Naval Enigma! You should run a single Bombe first to make sure your menu is good before attempting a multi-Bombe run.

You can see an example of using the Multiple Bombe operation to attack the above example message without knowing the rotor order in advance here.

What if I get far too many stops?

Use a longer or different crib. Try to find one that produces loops in the menu.

What if I get no stops, or only incorrect stops?

Are you sure your crib is correct? Try alternative cribs.

What if I know my crib is right, but I still don’t get any stops?

The middle rotor has probably stepped during the encipherment of your crib. Try a shorter or different crib.

How things work

How Enigma works

We won’t go into the full history of Enigma and all its variants here, but as a brief overview of how the machine works:

Enigma uses a series of letter->letter conversions to produce ciphertext from plaintext. It is symmetric, such that the same series of operations on the ciphertext recovers the original plaintext.

The bulk of the conversions are implemented in “rotors”, which are just an arbitrary mapping from the letters A-Z to the same letters in a different order. Additionally, to enforce the symmetry, a reflector is used, which is a symmetric paired mapping of letters (that is, if a given reflector maps X to Y, the converse is also true). These are combined such that a letter is mapped through three different rotors, the reflector, and then back through the same three rotors in reverse.

To avoid Enigma being a simple Caesar cipher, the rotors rotate (or “step”) between enciphering letters, changing the effective mappings. The right rotor steps on every letter, and additionally defines a letter (or later, letters) at which the adjacent (middle) rotor will be stepped. Likewise, the middle rotor defines a point at which the left rotor steps. (A mechanical issue known as the double-stepping anomaly means that the middle rotor actually steps twice when the left hand rotor steps.)

The German military Enigma adds a plugboard, which is a configurable pair mapping of letters (similar to the reflector, but not requiring that every letter is exchanged) applied before the first rotor (and thus also after passing through all the rotors and the reflector).

It also adds a ring setting, which allows the stepping point to be adjusted.

Later in the war, the Naval Enigma added a fourth rotor. This rotor does not step during operation. (The fourth rotor is thinner than the others, and fits alongside a thin reflector, meaning this rotor is not interchangeable with the others on a real Enigma.)

There were a number of other variants and additions to Enigma which are not currently supported here, as well as different Enigma networks using the same basic hardware but different rotors (which are supported by supplying your own rotor configurations).

How Typex works

Typex is a clone of Enigma, with a few changes implemented to improve security. It uses five rotors rather than three, and the rightmost two are static. Each rotor has more stepping points. Additionally, the rotor design is slightly different: the wiring for each rotor is in a removable core, which sits in a rotor housing that has the ring setting and stepping notches. This means each rotor has the same stepping points, and the rotor cores can be inserted backwards, effectively doubling the number of rotor choices.

Later models (from the Mark 22, which is the variant we simulate here) added two plugboards: an input plugboard, which allowed arbitrary letter mappings (rather than just pair switches) and thus functioned similarly to a configurable extra static rotor, and a reflector plugboard, which allowed rewiring the reflector.

How the Bombe works

The Bombe is a mechanism for efficiently testing and discarding possible rotor positions, given some ciphertext and known plaintext. It exploits the symmetry of Enigma and the reciprocal (pairwise) nature of the plugboard to do this regardless of the plugboard settings. Effectively, the machine makes a series of guesses about the rotor positions and plugboard settings and for each guess it checks to see if there are any contradictions (e.g. if it finds that, with its guessed settings, the letter A would need to be connected to both B and C on the plugboard, that’s impossible, and these settings cannot be right). This is implemented via careful connection of electrical wires through a group of simulated Enigma machines.

A full explanation of the Bombe’s operation is beyond the scope of this document – you can read the source code, and the authors also recommend Graham Ellsbury’s Bombe explanation, which is very clearly diagrammed.

Implementation in CyberChef

Enigma/Typex

Enigma and Typex were implemented from documentation of their functionality.

Enigma rotor and reflector settings are from GCHQ’s documentation of known Enigma wirings. We currently simulate all basic versions of the German Service Enigma; most other versions should be possible by manually entering the rotor wirings. There are a few models of Enigma, or attachments for the Service Enigma, which we don’t currently simulate. The operation was tested against some of GCHQ’s working examples of Enigma machines. Output should be letter-for-letter identical to a real German Service Enigma. Note that some Enigma models used numbered rather than lettered rotors – we’ve chosen to stick with the easier-to-use lettered rotors.

There were a number of different Typex versions over the years. We implement the Mark 22, which is backwards compatible with some (but not completely with all, as some early variants supported case sensitivity) older Typex models. GCHQ also has a partially working Mark 22 Typex. This was used to test the plugboards and mechanics of the machine. Typex rotor settings were changed regularly, and none have ever been published, so a test against real rotors was not possible. An example set of rotors have been randomly generated for use in the Typex operation. Some additional information on the internal functionality was provided by the Bombe Rebuild Project.

The Bombe

The Bombe was likewise implemented on the basis of documentation of the attack and the machine. The Bombe Rebuild Project at the National Museum of Computing answered a number of technical questions about the machine and its operating procedures, and helped test our results against their working hardware Bombe, for which the authors would like to extend our thanks.

Constructing menus from cribs in a manner that most efficiently used the Bombe hardware was another difficult step of operating the real Bombes. We have chosen to generate the menu automatically from the provided crib, ignore some hardware constraints of the real Bombe (e.g. making best use of the number of available Enigmas in the Bombe hardware; we simply simulate as many as are necessary), and accept that occasionally the menu selected automatically may not always be the optimal choice. This should be rare, and we felt that manual menu creation would be hard to build an interface for, and would add extra barriers to users experimenting with the Bombe.

The output of the real Bombe is optimised for manual verification using the checking machine, and additionally has some quirks (the rotor wirings are rotated by, depending on the rotor, between one and three steps compared to the Enigma rotors). Therefore, the output given is the ring position, and a correction depending on the rotor needs to be applied to the initial value, setting it to W for rotor V, X for rotor IV, and Y for all other rotors. We felt that this would require too much explanation in CyberChef, so the output of CyberChef’s Bombe operation is the initial value for each rotor, with the ring positions set to A, required to decrypt the ciphertext starting at the beginning of the crib. The actual stops are the same. This would not have caused problems at Bletchley Park, as operators working with the Bombe would never have dealt with a real or simulated Enigma, and vice versa.

By default the checking machine is run automatically and stops which fail silently discarded. This can be disabled in the operation configuration, which will cause it to output all stops from the actual Bombe hardware instead. (In this case you only get one stecker pair, rather than the set identified by the checking machine.)

Optimisation

A three-rotor Bombe run (which tests 17,576 rotor positions and takes about 15-20 minutes on original Turing Bombe hardware) completes in about a fifth of a second in our tests. A four-rotor Bombe run takes about 5 seconds to try all 456,976 states. This also took about 20 minutes on the four-rotor US Navy Bombe (which rotates about 30 times faster than the Turing Bombe!). CyberChef operations run single-threaded in browser JavaScript.

We have tried to remain fairly faithful to the implementation of the real Bombe, rather than a from-scratch implementation of the underlying attack. There is one small deviation from “correct” behaviour: the real Bombe spins the slow rotor on a real Enigma fastest. We instead spin the fast rotor on an Enigma fastest. This means that all the other rotors in the entire Bombe are in the same state for the 26 steps of the fast rotor and then step forward: this means we can compute the 13 possible routes through the lower two/three rotors and reflector (symmetry means there are only 13 routes) once every 26 ticks and then save them. This does not affect where the machine stops, but it does affect the order in which those stops are generated.

The fast rotors repeat each others’ states: in the 26 steps of the fast rotor between steps of the middle rotor, each of the scramblers in the complete Bombe will occupy each state once. This means we can once again store each state when we hit them and reuse them when the other scramblers rotate through the same states.

Note also that it is not necessary to complete the energisation of all wires: as soon as 26 wires in the test register are lit, the state is invalid and processing can be aborted.

The above simplifications reduce the runtime of the simulation by an order of magnitude.

If you have a large attack to run on a multiprocessor system – for example, the complete M4 Naval Enigma, which features 1344 possible choices of rotor and reflector configuration, each of which takes about 5 seconds – you can open multiple CyberChef tabs and have each run a subset of the work. For example, on a system with four or more processors, open four tabs with identical Multiple Bombe recipes, and set each tab to a different combination of 4th rotor and reflector (as there are two options for each). Leave the full set of eight primary rotors in each tab. This should complete the entire run in about half an hour on a sufficiently powerful system.

s2224834 (GCHQ, via GitHub)

To celebrate their centenary, GCHQ have open-sourced very-faithful reimplementations of Enigma, Typex, and Bombe that you can run in your browser. That’s pretty cool, and a really interesting experimental toy for budding cryptographers and cryptanalysts!

Logitech MX Master 2S

I’m a big believer in the idea that the hardware I lay my hands on all day, every day, needs to be the best for its purpose. On my primary desktop, I type on a Das Keyboard 4 Professional (with Cherry MX brown switches) because it looks, feels, and sounds spectacular. I use the Mac edition of the keyboard because it, coupled with a few tweaks, gives me the best combination of features and compatibility across all of the Windows, MacOS, and Linux (and occasionally other operating systems) I control with it. These things matter.

I also care about the mouse I use. Mice are, for the most part, for the Web and for gaming and not for use in most other applications (that’s what keyboard shortcuts are for!) but nonetheless I spend plenty of time holding one and so I want the tool that feels right to me. That’s why I was delighted when, in replacing my four year-old Logitech MX1000 in 2010 with my first Logitech Performance MX, I felt able to declare it the best mouse in the world. My Performance MX lived for about four years, too – that seems to be how long a mouse can stand the kind of use that I give it – before it started to fail and I opted to replace it with an identical make and model. I’d found “my” mouse, and I was sticking with it. It’s a great shape (if you’ve got larger hands), is full of features including highly-configurable buttons, vertical and horizontal scrolling (or whatever you want to map them to), and a cool “flywheel” mouse wheel that can be locked to regular operation or unlocked for controlled high-speed scrolling at the touch of a button: with practice, you can even use it as a speed control by gently depressing the switch like it was a brake pedal. Couple all of that with incredible accuracy on virtually any surface, long battery life, and charging “while you use” and you’ve a recipe for success, in my mind.

My second Performance MX stopped properly charging its battery this week, and it turns out that they don’t make them any more, so I bought its successor, the Logitech MX Master 2S.

The MX Master 2S is… different… from its predecessor. Mostly in good ways, sometimes less-good. Here’s the important differences:

Matte coating: only the buttons are made of smooth plastic; the body of the mouse is now a slightly coarser plastic: you’ll see in the photo above how much less light it reflects. It feels like it would dissipate heat less-well.
Horizontal wheel replaces rocker wheel: instead of the Performance MX’s “rocker” scroll wheel that can be pushed sideways for horizontal scroll, the MX Master 2S adds a dedicated horizontal scroll (or whatever you reconfigure it to) wheel in the thumb well. This is a welcome change: the rocker wheel in both my Performance MXes became less-effective over time and in older mice could even “jam on”, blocking the middle-click function. This seems like a far more-logical design.
New back/forward button shape: to accommodate the horizontal wheel, the “back” and “forward” buttons in the thumb well have been made smaller and pushed closer together. This is the single biggest failing of the MX Master 2S: it’s clearly a mouse designed for larger hands, and yet these new buttons are slightly, but noticeably, harder to accurately trigger with a large thumb! It’s tolerable, but slightly annoying.
Bluetooth support: one of my biggest gripes about the Performance MX was its dependence on Unifying, Logitech’s proprietary wireless protocol. The MX Master 2S supports Unifying but also supports Bluetooth, giving you the best of both worlds.
Digital flywheel: the most-noticable change when using the mouse is the new flywheel and braking mechanism, which is comparable to the change in contemporary cars from a mechanical to a digital handbrake. The flywheel “lock” switch is now digital, turning on or off the brake in a single stroke and so depriving you of the satisfaction of using it to gradually “slow down” a long spin-scroll through an enormous log or source code file. But in exchange comes an awesome feature called SmartShift, which dynamically turns on or off the brake (y’know, like an automatic handbrake!) depending on the speed with which you throw the wheel. That’s clever and intuitive and “just works” far better than I’d have imagined: I can choose to scroll slowly or quickly, with or without the traditional ratchet “clicks” of a wheel mouse, with nothing more than the way I flick my finger (and all fully-configurable, of course). And I’ve still got the button to manually “toggle” the brake if I need it. It took some getting used to, but this change is actually really cool! (I’m yet to get used to the sound of the digital brake kicking in automatically, but that’s true of my car too).
Basic KVM/multi-computing capability: with a button on the underside to toggle between different paired Unifying/Bluetooth transceivers and software support for seamless edge-of-desktop multi-computer operation, Logitech are clearly trying to target folks who, like me, routinely run multiple computers simultaneously from a single keyboard and mouse. But it’s a pointless addition in my case because I’ve been quite happy using Synergy to do this for the last 7+ years, which does it better. Still, it’s a harmless “bonus” feature and it might be of value to others, I suppose.

All in all, the MX Master 2S isn’t such an innovative leap forward over the Performance MX as the Performance MX was over the MX1000, but it’s still great that this spectacular series of heavyweight workhouse feature-rich mice continues to innovate and, for the most part, improve upon the formula. This mouse isn’t cheap, and it isn’t for everybody, but if you’re a big-handed power user with a need to fine-tune all your hands-on hardware to get it just right, it’s definitely worth a look.

The “Backendification” of Frontend Development

This article is a repost promoting content originally published elsewhere. See more things Dan's reposted.

https://hackernoon.com/the-backendification-of-frontend-development-62f218a773d4 (hackernoon.com)

Asynchronous JavaScript in the form of Single Page Applications (SPA) offer an incredible opportunity for improving the user experience of your web applications. CSS frameworks like Bootstrap enable developers to quickly contribute styling as they’re working on the structure and behaviour of things.

Unfortunately, SPA and CSS frameworks tend to result in relatively complex solutions where traditionally separated concerns – HTML-structure, CSS-style, and JS-behaviour – are blended together as a matter of course — Counter to the lessons learned by previous generations.

This blending of concerns can prevent entry level developers and valued specialists (Eg. visual design, accessibility, search engine optimization, and internationalization) from making meaningful contributions to a project.

In addition to the increasing cost of the few developers somewhat capable of juggling all of these concerns, it can also result in other real world business implications.

…

Mike Taylor (Hackernoon)

What is a front-end developer? Does anybody know, any more? And more-importantly, how did we get to the point where we’re actively encouraging young developers into habits like writing (cough React cough) files containing a bloaty, icky mixture of content, HTML (markup), CSS (style), and Javascript (behaviour)? Yes, I get that the idea is that individual components should be packaged together (if you’re thinking in a React-like worldview), but that alone doesn’t justify this kind of bullshit antipattern.

It seems like the Web used to have developers. Then it got complex so we started differentiating back-end from front-end developers and described those who, like me, spanned the divide, as full-stack developers We gradually became a minority as more and more new developers, deprived of the opportunity to learn each new facet organically in this newly-complicated landscape, but that’s fine. But then… we started treating the front-end as the only end, and introducing all kinds of problems as a result… and most people don’t seem to have noticed, yet, exactly how much damage we’re doing to Web applications’ security, maintainability, future-proofibility, archivability, addressibility…

Pac-Man: The Untold Story of How We Really Played The Game

This article is a repost promoting content originally published elsewhere. See more things Dan's reposted.

…

Human beings leave physical impressions upon the things they love and use just as much as their do upon the lives of people and the planet they live upon. For every action, there’s a reaction. For every pressure, there’s an affect on mass and volume. And in the impressions left by that combination, particularly if you’re lucky enough to see the sides of a rare, unrestored vintage Pac-Man cabinet, lies the never before told story of how we really played the game.

Until now, I don’t believe anyone has ever written about it.

…

Cat DeSpira

Interesting exploration of the history of the cabinets housing Pac-Man, observing the ergonomic impact of the controls on the way that people would hold the side of the machine and, in turn, how that would affect where and how the paint would wear off.

I love that folks care about this stuff.

Debugging WorldWideWeb

Earlier this week, I mentioned the exciting hackathon that produced a moderately-faithful reimagining of the world’s first Web browser. I was sufficiently excited about it that I not only blogged here but I also posted about it to MetaFilter. Of course, the very first thing that everybody there did was try to load MetaFilter in it, which… didn’t work.

MetaFilter failing to load on the reimagined WorldWideWeb. — 500? Really?

People were quick to point this out and assume that it was something to do with the modernity of MetaFilter:

honestly, the disheartening thing is that many metafilter pages don’t seem to work. Oh, the modern web.

— Going To Maine

Some even went so far as to speculate that the reason related to MetaFilter’s use of CSS and JS:

CSS and JS. They do things. Important things.

— GuyZero

This is, of course, complete baloney, and it’s easy to prove to oneself. Firstly, simply using the View Source tool in your browser on a MetaFilter page reveals source code that’s quite comprehensible, even human-readable, without going anywhere near any CSS or JavaScript.

Secondly, it’s pretty simple to try browsing MetaFilter without CSS or JavaScript enabled! I tried in two ways: first, by using Lynx, a text-based browser that’s never supported either of those technologies. I also tried by using Firefox but with them disabled (honestly, I slightly miss when the Web used to look like this):

And thirdly: the error code being returned by the simulated WorldWideWeb browser is a HTTP code 500. Even if you don’t know your HTTP codes (I mean, what kind of weirdo would take the time to memorise them all anyway <ahem>), it’s worth learning this: the first digit of a HTTP response code tells you what happened:

1xx means “everything’s fine, keep going”;
2xx means “everything’s fine and we’re done”;
3xx means “try over there”;
4xx means “you did something wrong” (the infamous 404, for example, means you asked for a page that doesn’t exist);
5xx means “the server did something wrong”.

Simple! The fact that the error code begins with a 5 strongly implies that the problem isn’t in the (client-side) reimplementation of WorldWideWeb: if this had have been a CSS/JS problem, I’d expect to see a blank page, scrambled content, “filler” content, or incomplete content.

So I found myself wondering what the real problem was. This is, of course, where my geek flag becomes most-visible: what we’re talking about, let’s not forget, is a fringe problem in an incomplete simulation of an ancient computer program that nobody uses. Odds are incredibly good that nobody on Earth cares about this except, right now, for me.

Dan's proposed "Geek Flag" — I searched for a “Geek Flag” and didn’t like anything I saw, so I came up with this one based on… well, if you recognise what it’s based on, good for you, you’re certainly allowed to fly it. If not… well, you can too: there’s no geek-gatekeeping here.

Luckily, I spotted Jeremy’s note that the source code for the WorldWideWeb simulator was now available, so I downloaded a copy to take a look. Here’s what’s happening:

The (simulated) copy of WorldWideWeb is asked to open a document by reference, e.g. “https://www.metafilter.com/”.
To work around same-origin policy restrictions, the request is sent to an API which acts as a proxy server.
The API makes a request using the Node package “request” with this line of code: request(url, (error, response, body) => { ... }). When the first parameter to request is a (string) URL, the module uses its default settings for all of the other options, which means that it doesn’t set the User-Agent header (an optional part of a Web request where the computer making the request identifies the software that’s asking).
MetaFilter, for some reason, blocks requests whose User-Agent isn’t set. This is weird! And nonstandard: while web browsers should – in RFC2119 terms – set their User-Agent: header, web servers shouldn’t require that they do so. MetaFilter returns a 403 and a message to say “Forbidden”; usually a message you only see if you’re trying to access a resource that requires session authentication and you haven’t logged-in yet.
The API is programmed to handle response codes 200 (okay!) and 404 (not found), but if it gets anything else back it’s supposed to throw a 400 (bad request). Except there’s a bug: when trying to throw a 400, it requires that an error message has been set by the request module and if there hasn’t… it instead throws a 500 with the message “Internal Server Fangle” and no clue what actually went wrong. So MetaFilter’s 403 gets translated by the proxy into a 400 which it fails to render because a 403 doesn’t actually produce an error message and so it gets translated again into the 500 that you eventually see. What a knock-on effect!

Illustration showing conversation between simulated WorldWideWeb and MetaFilter via an API that ultimately sends requests without a User-Agent, gets a 403 in response, and can't handle the 403 and so returns a confusing 500. — If you’re having difficulty visualising the process, this diagram might help you to continue your struggle with that visualisation.

The fix is simple: simply change the line:

request(url, (error, response, body) => { ... })

to:

request({ url: url, headers: { 'User-Agent': 'WorldWideWeb' } }, (error, response, body) => { ... })

This then sets a User-Agent header and makes servers that require one, such as MetaFilter, respond appropriately. I don’t know whether WorldWideWeb originally set a User-Agent header (CERN’s source file archive seems to be missing the relevant C sources so I can’t check) but I suspect that it did, so this change actually improves the fidelity of the emulation as a bonus. A better fix would also add support for and appropriate handling of other HTTP response codes, but that’s a story for another day, I guess.

I know the hackathon’s over, but I wonder if they’re taking pull requests…

CSS-driven console graphics

If you’re reading this post via my blog and using a desktop computer, try opening your browser’s debug console (don’t worry; I’ll wait). If you don’t know how, here’s instructions for Firefox and instructions for Chrome. Other browsers may vary. You ought to see something like this in your debugger:

What sorcery is this?

The debug console is designed to be used by web developers so that they can write Javascript code right in their browser as well as to investigate any problems with the code run by a web page. The web page itself can also output to the console, which is usually used for what I call “hello-based debugging”: printing out messages throughout a process so that the flow and progress can be monitored by the developer without having to do “proper” debugging. And it gets used by some web pages to deliver secret messages to any of the site users who open their debugger.

Facebook console messaging advising against the use of the console. — Facebook writes to the console a “stop” message, advising against using the console unless you know what you’re doing in an attempt to stop people making themselves victims of console-based social engineering attacks.

Principally, though, the console is designed for textual content and nothing else. That said, both Firefox and Chrome’s consoles permit the use of CSS to style blocks of debug output by using the %c escape sequence. For example, I could style some of a message with italic text:

>> console.log('I have some %citalic %ctext', 'font-style: italic;', ''); I have some italic text

Using CSS directives like background, then, it’s easy to see how one could embed an image into the console, and that’s been done before. Instead, though, I wanted to use the lessons I’d learned developing PicInHTML 8¾ years ago to use text and CSS (only) to render a colour picture to the console. First, I created my template image – a hackergotchi of me and an accompanying speech bubble, shrunk to a tiny size and posterised to reduce the number of colours used and saved as a PNG.

Hackergotchi of Dan with a speech bubble, "squashed". — The image appears “squashed” to compensate for console monospace letters not being “square”.

Next, I wrote a quick Ruby program, consolepic.rb, to do the hard work. It analyses each pixel of the image and for each distinct colour assigns to a variable the CSS code used to set the background colour to that colour. It looks for “strings” of like pixels and combines them into one, and then outputs the Javascript necessary to write out all of the above. Finally, I made a few hand-tweaks to insert the text into the speech bubble.

The resulting output weighs in at 31.6kB – about a quarter of the size of the custom Javascript on the frontend of my site and so quite a bit larger than I’d have liked and significantly less-efficient than the image itself, even base64-encoded for embedding directly into the code, but that really wasn’t the point of the exercise, was it? (I’m pretty sure there’s significant room for improvement from a performance perspective…)

Scatmania.org in 2012 — I’ll be first to admit it’s not as cool as the “pop-up Dan” in the corner of my 2012 design. You might enjoy my blog post about my 20 years of blogging or the one about how “pop-up Dan” worked.

What it achieved was an interesting experiment into what can be achieved with Javascript, CSS, the browser console, and a little imagination. An experiment that can live here on my site, for anybody who looks in the direction of their debugger, for the foreseeable future (or until I get bored of it). Anybody with any more-exotic/silly ideas about what this technique could be used for is welcome to let me know!

Update: 17 April 2019 – fun though this was, it wasn’t worth continuing to deliver an additional 25% Javascript payload to every visitor just for this, so I’ve stopped it for now. You can still read the source code (and even manually run it in the console) if you like. And I have other ideas for fun things to do with the console, so keep an eye out for that…

Note #10619

@adactio: The ampersand in https://adactio.com/notes/14395 isn’t being properly escaped in your RSS feed, breaking the XML – see e.g. https://validator.w3.org/feed/check.cgi?url=https%3A%2F%2Fadactio.com%2Frss

The Mystery Button-Box

Earlier this year I found a mystery cable. But today, I’ve got an even bigger mystery. What the hell is this?

I found it in a meeting room at work, tucked away in a corner. Aside from the power cord, there are no obvious interfaces to it.

My best bet is that it’s some kind of induction-based charger? I imagine some kind of device like a radio microphone or walkie-talkie that can be pushed-in to these holes and the button “spring” is just about closing the hole when it’s not in use. But the box is old, based on the style of plug, cable, and general griminess of the hardware… not to mention that it’s got a stack of PAT test stickers going back at least 11 years.

I’ve plugged it in and tried “pressing” the buttons but it doesn’t appear to do anything, which supports my “induction charger” hypothesis. But what does it charge? I must know!

Edit: The only Electrak I can find make lighting control systems. Could it be something to do with lighting control? I can’t find anything that looks like this on their website, though.

Edit 2: Ah-hah! Looks like it’s some weird kind of electrical socket. You put the key-shaped plug in and “twist”.

Electrak plug — The plugs apparently look something like this, although I can’t find any here.

Edit 3: Hang on a minute… the most-recent PAT test sticker indicates that it was tested in… November 2019. Now my working hypothesis is that this is some kind of power supply system for a time machine we haven’t yet built. I’ve asked a number of colleagues what it’s for (i.e. what plugs into it) and nobody seems to have a clue.

The Alice and Bob After Dinner Speech

This article is a repost promoting content originally published elsewhere. See more things Dan's reposted.

John Gordon: The Alice and Bob After Dinner Speech (urbigenous.net)

Good evening Ladies and Gentlemen.

There comes a time when people at a technical conference like this need something more relaxing. A change of pace. A shift of style. To put aside all that work stuff and think of something refreshingly different.

So let’s talk about coding theory. There are perhaps some of you here tonight who are not experts in coding theory, but rather have been dragged here kicking and screaming. So I thought it would be a good idea if I gave you a sort of instant, five minute graduate course in coding theory.

Coding theorists are concerned with two things. Firstly and most importantly they are concerned with the private lives of two people called Alice and Bob. In theory papers, whenever a coding theorist wants to describe a transaction between two parties he doesn’t call then A and B. No. For some longstanding traditional reason he calls them Alice and Bob.

Now there are hundreds of papers written about Alice and Bob. Over the years Alice and Bob have tried to defraud insurance companies, they’ve played poker for high stakes by mail, and they’ve exchanged secret messages over tapped telephones.

If we put together all the little details from here and there, snippets from lots of papers, we get a fascinating picture of their lives. This may be the first time a definitive biography of Alice and Bob has been given.

In papers written by American authors Bob is frequently selling stock to speculators. From the number of stock market deals Bob is involved in we infer that he is probably a stockbroker. However from his concern about eavesdropping he is probably active in some subversive enterprise as well. And from the number of times Alice tries to buy stock from him we infer she is probably a speculator. Alice is also concerned that her financial dealings with Bob are not brought to the attention of her husband. So Bob is a subversive stockbroker and Alice is a two-timing speculator.

But Alice has a number of serious problems. She and Bob only get to talk by telephone or by electronic mail. In the country where they live the telephone service is very expensive. And Alice and Bob are cheapskates. So the first thing Alice must do is MINIMIZE THE COST OF THE PHONE CALL.

The telephone is also very noisy. Often the interference is so bad that Alice and Bob can hardly hear each other. On top of that Alice and Bob have very powerful enemies. One of their enemies is the Tax Authority. Another is the Secret Police. This is a pity, since their favorite topics of discussion are tax frauds and overthrowing the government.

These enemies have almost unlimited resources. They always listen in to telephone conversations between Alice and Bob. And these enemies are very sneaky. One of their favorite tricks is to telephone Alice and pretend to be Bob.

Well, you think, so all Alice has to do is listen very carefully to be sure she recognizes Bob’s voice. But no. You see Alice has never met Bob. She has no idea what his voice sounds like.

So you see Alice has a whole bunch of problems to face. Oh yes, and there is one more thing I forgot so say – Alice doesn’t trust Bob. We don’t know why she doesn’t trust him, but at some time in the past there has been an incident.

Now most people in Alice’s position would give up. Not Alice. She has courage which can only be described as awesome. Against all odds, over a noisy telephone line, tapped by the tax authorities and the secret police, Alice will happily attempt, with someone she doesn’t trust, whom she cannot hear clearly, and who is probably someone else, to fiddle her tax returns and to organize a coup d’etat, while at the same time minimizing the cost of the phone call.

A coding theorist is someone who doesn’t think Alice is crazy.

…

John Gordon

I’ve always been a fan of the “expanded universe” of cyptography placeholders Alice & Bob, and this humorous speech – partially-reproduced here – is a great example of Alice & Bob headcanon at its best.