3 HN users recommended this explainer3 months2021–2024score 3
Years with an HN recommendation, 2007–2026
HN recommends it as a good starting point on practical Enigma cryptanalysis with modern hardware.
Dr Mike Pound of Computerphile shows how a modern laptop can crack Enigma, using a ciphertext-only attack based on an older paper. He compares it with the tooling in CrypTool.
Super interesting, thanks! This is also a good companion video -- [this video] -- about the feasibility of cracking Enigma "in 2021" i.e. using computational power available to us today. TLDW & AFAIK: it's crackable (just as it was back then, using a bag of approaches & heuristics), but you still couldn't plain brute force an encrypted message today if you didn't have any portion of the plain text, the Enigma was using 10 plugboard pairs, etc. Also see [link]
Feasibility of cracking Enigma with modern compute
AFAIK the Germans kept improving both the Enigma itself and the procedures for using it. For example there was some specific weakness that the Polish attacks used, but at some point Germans figured it out and "patched" it. By the end of the war they could change the "encryption key" even more often than once a day, whereas before the war they could reuse the same key for many months. The Poles didn't break all Enigma setups till 1939 because one didn't have to it yet to effectively collect intelligence. Also because they hadn't existed yet :) Enigma was actually pretty good, but it had a major design flaw: insufficient diffusion. The YouTube channel Computerphile made a good video on practical cryptanalysis of the Enigma using modern hardware: [this video] . In short, if you know what you're doing you can do ciphertext-only attacks given long enough messages and minimal knowledge about the distribution of the plaintext (their example relies only on the fact that the plaintext is in English).
An episode of Computerphile attempted to answer the question - [this video] . TL;DW: With some clever tricks, and the advantage of hindsight, it can be done reasonably quickly on a modern computer.
Enigma can be cracked quickly on a modern computer
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