
Enigma code-breaking machine rebuilt at Cambridge - LogicRiver
https://techxplore.com/news/2020-07-enigma-code-breaking-machine-rebuilt-cambridge.html
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rgovostes
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](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.

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

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tehbeard
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)

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tialaramex
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.

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Nuzzerino
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](https://www.youtube.com/watch?v=G2_Q9FoD-oQ)

~~~
Rebelgecko
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!

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acd
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.

