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by azag0 3002 days ago
Enigma wasn't hard through obscurity. The Allies had the Enigma machine long before they were able to crack it. It was hard because with the equipment of the day, it was pretty much unbreakable in the same way that prime-number based cryptography is today. It was only A. Turing developing a completely novel kind of machine (https://en.wikipedia.org/wiki/Bombe) that enabled the decryption. In the same way that quantum computers could break the current cryptography easily. It's not obscurity, it's assuming that some (mathematical) task is hard.
1 comments
JetSpiegel 3002 days ago
Don't forget about the Polish. They too broke the encryption before, but then they were invaded, and no precision machinery was available to increase the number of rotors to 10. https://en.m.wikipedia.org/wiki/Cryptanalysis_of_the_Enigma Turing did it too, independently.
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azag0 3002 days ago
Didn't know about that! But it seems they were able to break the system only while the Germans where sending the settings of the plugboard in the header of each message. Once that was changed in the early 1940, their decrypting techniques wouldn't work anymore.

Btw, from the wikipedia article: "lazy cipher clerks often chose starting positions such as "AAA", "BBB", or "CCC"" Weak passwords were an issue already back then.

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Moodles 3002 days ago
I went to Bletchley Park a couple of years ago. It's a very fascinating place. I remember hearing stories of code breakers who could infer that a piece of plaintext was all JJJJJJJJJJJ simply because, upon looking at the ciophertext, it contained no J (relying on the fact that no letter would ever encrypt to itself in Engima, because of the reflector). Indeed the Poles don't get enough credit for their contributions. And yeah, virtually all encryption was similar to Engima back then: the Allies too had a similar machine. I believe traitors sold secrets or Engimas were captures on U-boats and so on, so security through obscurity wasn't really a thing back then either.
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GTP 3002 days ago
From what I know Turing didn't do it independently: the Polish sent their work to England about two months before being invaded, what Turing did is improve on their work so it could scale (the Germans added more rotors so the Polish decrypting machine wasn't helpful anymore).
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e12e 3002 days ago
See also the Swedish who cracked the t52:

https://www.wired.com/2007/08/looking-back-at/

https://en.m.wikipedia.org/wiki/Arne_Beurling

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