Enigma Code-Breaking Machine Rebuilt At Cambridge (techxplore.com) 34
Cambridge Engineering alumnus Hal Evans has built a fully-functioning replica of a 1930s Polish cyclometer -- an electromechanical cryptologic device that was designed to assist in the decryption of German Enigma ciphertext. The replica currently resides in King's College, Cambridge. TechXplore reports: Work on the hardware-based replica began in 2018, as part of Hal's fourth year Master's project under the supervision of King's College Fellow and Senior Tutor Dr. Tim Flack. The aim was to investigate further into cryptologist Marian Rejewski's cyclometer -- an early forerunner to Cambridge University mathematician Alan Turing's machine, known as the Bombe, which was used to crack the German Enigma code during the Second World War. Hal said he chose to work on the cyclometer as it was the very first machine used to assist the decryption effort. To his knowledge, the replica is the first fully-functioning hardware-based electromechanical cyclometer to exist since the years preceding the Second World War. The original machines would have been destroyed in 1939 to prevent them from falling into the hands of German invaders.
Rejewski's cyclometer exploited the German's procedure at the time of double encipherment of the Enigma message key, and semi-automated the process for calculating what were known as 'characteristics' for every possible Enigma rotor starting position. There were more than 100,000 of these rotor starting positions, and they each needed their characteristic to be calculated and catalogued in a card index system. The cyclometer therefore eliminated the arduous task of calculating these characteristics by hand. The machine consisted of, in effect, two interlinked Enigma systems side-by-side -- one offset by three positions relative to the other -- and 26 lamps and switches to cover the alphabet. On operation, a certain number of bulbs illuminated, indicating the lengths of the characteristics. These were recorded for every single possible rotor starting position to create an immense look-up catalogue. Once this was completed, obtaining the daily Enigma rotor starting settings to decode messages was a simple matter of intercepting enough messages and referencing the catalogue, taking only a matter of minutes.
Rejewski's cyclometer exploited the German's procedure at the time of double encipherment of the Enigma message key, and semi-automated the process for calculating what were known as 'characteristics' for every possible Enigma rotor starting position. There were more than 100,000 of these rotor starting positions, and they each needed their characteristic to be calculated and catalogued in a card index system. The cyclometer therefore eliminated the arduous task of calculating these characteristics by hand. The machine consisted of, in effect, two interlinked Enigma systems side-by-side -- one offset by three positions relative to the other -- and 26 lamps and switches to cover the alphabet. On operation, a certain number of bulbs illuminated, indicating the lengths of the characteristics. These were recorded for every single possible rotor starting position to create an immense look-up catalogue. Once this was completed, obtaining the daily Enigma rotor starting settings to decode messages was a simple matter of intercepting enough messages and referencing the catalogue, taking only a matter of minutes.
Re: (Score:2)
Re:Where exactly? (Score:5, Funny)
Re: (Score:2)
Someone who has never heard of "Miami" may well appreciate such a clarification.
Just as someone who's heard of Cambridge, Mass, but never of Cambridge University (UK), may appreciate some clarification.
Re: (Score:2)
Interesting point, but I disagree. Perhaps when one mentions "Cambridge" if it's not obvious from context whether it's the UK or Massachusetts, then one should clarify, but "Cambridge University" without qualification is normally taken as the original Cambridge University in the UK. I guess from your post that there is a university of Cambridge, Mass, but it is nowhere near as famous a Cambridge University in the UK.
Re: (Score:2)
Isn't the US one called Harvard rather than Cambridge University?
Re: (Score:2)
Isn't the US one called Harvard rather than Cambridge University?
Spot on - Harvard University is the pre-eminent university of Cambridge, Massachusetts. If there is also a "University of Cambridge" there, then it is not in the least well known. With MIT also there, there isn't much room in the global namespace for lesser known colleges in Massachusetts.
Re: (Score:2)
When you talk about Cambridge University, it would be helpful to mention if it is in the UK or the USA.
King's College, Cambridge right there in TFS
Given the context - Enigma code breaking - why would you not guess Alan Turing's Cambridge anyway?
+1 Didn't Read Summary
-2 Geek Card Revoked
Re: (Score:3)
Re: (Score:2)
Well played.
Re: (Score:2)
In point of fact it was Polish, and it was a device that assisted in cracking the Enigma.
Re: (Score:2)
I'd rather be a white knight than an webmaster who thinks he's god
...unbreakable? (Score:2)
Imagine adding a gear or two to the cipher AND combining with a 2nd new complication.
-r
Re:...unbreakable? (Score:5, Informative)
That’s what the German Navy did towards the end of the war for their Uboats models. They required a 4th wheel to the settings and added 3 more wheels to the pool. So instead of picking 3 out of 5 possible wheels, it was now 4 out of 8. Also all the code books were changed. Bletchley Park was unable to decode Uboat messages for 10 months. Then it was discovered that while the Uboats upgraded their Enigma to M4 machines, their land based counterparts did not and still used M3 machines. There had to be backwards compatibility with the new versions and the old. Painstaking analysis of these ship to shore messages were able to reverse engineer these new wheels.
Re: (Score:2)
Nazi flag guy (Score:3)
Where's the Nazi flag guy?