Enigma code-breaking machine rebuilt at Cambridge | Hacker News Reader

Enigma code-breaking machine rebuilt at Cambridge

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68 pointsLogicRiver10 comments

A rebuilt and operational Bombe---the machine Alan Turing worked on---is also on display at the Bletchley Park museum. https://www.bombe.org.uk

Several years ago I contacted the rebuild team inquiring about getting mechanical drawings of the bombe. They told me there are about 4,000 original drawings in the GCHQ archives that require special permission to access, and the team redrew about 2,500 of these in AutoCAD to create the reconstruction.

Unfortunately they don't share their files ("the property of the Bombe Rebuild Project team and are not made generally available"). I respect the enormity of the effort, but I wish they were willing to share it beyond a single replica in a museum an hour outside of London. I assume that one does not embark on such a project because it is lucrative.

I highly recommend spending an entire day at Bletchley Park. They have lots of activities for children too. The operational bombe was fascinating

I'd also recommend a visit to the national museum of computing next door* to Bletchley Park to see a working replica of colossus and lots of other computing history. Do check their opening times though as they did not line up with BPs exactly.

(*Technically "on site", it's weird the relationship between the two)

Both the Bombe replica and Colossus are now technically part of the National Museum of Computing rather than the Bletchley Park exhibits. But yes, check the opening times to ensure you can just see everything unless you live very nearby.

Colossus is more interesting not only from a Computing History point of view but also cryptographically.

Engima, though more famous, was a cryptographic cul-de-sac. It's the ultimate expression of a way of encrypting things that had already become more or less obsolete. The Bombes likewise are the extreme end of mechanical brute force attacks on such cryptography. They're both fiendishly clever, but in a way were already obsolete when WW2 broke out.

Lorenz though is in some sense an ancestor of cryptography you're using today. It's a stream cipher. The key is used to arrange for a stream of random-seeming bits to be generated, you XOR the bits with the message to get ciphertext, your opposite number generates the same stream with the same key, XORs the ciphertext and gets back the message.

Now, for Lorenz each symbol has only 5-bits whereas today we think in 8-bit bytes, but that's not a big deal. The general shape of the system is almost what you'd build today.

And so likewise Colossus is almost a modern computer. It was digital and electronic, and even programmable, but since the programming involves essentially taking the machine to pieces it's not quite a modern stored program digital computer. In practice Colossus served one purpose, to break Lorenz as part of the Ultra secret. As Bletchley cryptanalysts understood more about Lorenz they could reprogram Colossus to try new things.

This. It’s super non-obvious if you go that there’s more to see. No signage or anything. I’m disappointed I missed the national museum of computing (though Bletchley itself was awesome!)

A report (from a mathematician, cum grano salis) on Churchill's take on SIGINT vs HUMINT:

https://news.ycombinator.com/item?id=23597523

(for a brief moment I misinterpreted IMINT as an abbreviation for "Imaginary Intelligence". I've read a biography of Michael Collins which suggests that more of the irish war of independence was conducted by disappearing or altering files in the british records than one might naively think.)

A fun way to learn more about the original mathematicians involved in cracking the codes and later creating the cyclometers, is to see the movie "Battle of Warsaw 1920". It is a wild movie about the Polish Russia war. There is a group of mathematicians that we meet in the movie, who decide they want to do their part to defend Warsaw, against the Bolsheviks. Their treatment - familiar, and their actions - brilliant; make for a somewhat humorous, but also educational story. You also learn about the last cavalry campaign, and this little known movie about a little known war, which was historically extremely important(to Europe, and therefore to the West.) (Find it with subtitles!)

Here is an interesting video by Numberphile on the Enigma machine, for anyone curious on the details of its inner workings: https://www.youtube.com/watch?v=G2_Q9FoD-oQ

If anyone finds this intriguing and happens to be in the DC Area, the NSA's crypto museum has 2 Engima machines and one of the US built bombes (which used a moderately different design than the British ones).

The bombe exhibit is cool, but the enigma machines are a highlight because you can actually use them. Because encryption and decryption are the same function (kinda like CTR mode), it's pretty easy to generate a string of gibberish that makes the display light up with profanity (don't forget to roll back the rotors). Fun for all ages!

Thankful to Alan Turing for creating the Turing machine which compilers and this computers rely on. Thankful for Alan Turing breaking the German Enigma crypto together with the Polish crypto breakers so the west could listen to Nazi War communication and we got rid of them winning the war. Alan Turing was gay and was not treated well by the UK government something the UK government later made an apology for. Also grateful to the Russian WWII effort wish I could have seen the 75th year memory victory parade this year. Thanks to all Americans Soldiers for saving us.

Grateful that the crypto Enigma breaker has been rebuilt.

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