ANN: obfuscate
in [Python]
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From: Tim Golden on 10 Feb 2010 06:27 On 10/02/2010 11:23, Simon Brunning wrote: > "Hello World!".encode('rot-13') Not any more! <dump> Python 3.1.1 (r311:74483, Aug 17 2009, win32 Type "help", "copyright", "credits" or >>> "Hello World!".encode('rot-13') Traceback (most recent call last): File "<stdin>", line 1, in <module> LookupError: unknown encoding: rot-13 >>> </dump> TJG
From: Gregory Ewing on 11 Feb 2010 02:59 Christian Heimes wrote: > A much, much stronger version of the > principles behind Vigenère was used in the German Enigma machine. > Because the algorithm was still not good enought some clever guy called > Turing and his team was able to crack the enigma. Actually I gather it had a lot to do with the fact that the Germans made some blunders in the way they used the Enigma that seriously compromised its security. There was reportedly a branch of the German forces that used their Enigmas differently, avoiding those mistakes, and the British never managed to crack any of their messages. -- Greg
From: Gregory Ewing on 11 Feb 2010 03:01 Daniel Fetchinson wrote: > It also turned out that everybody mostly writes his/her > own obfuscation routine. Hey, it gives you the additional advantage of obfuscation by obscurity! -- Greg
From: Paul Rubin on 11 Feb 2010 06:32 Gregory Ewing <greg.ewing(a)canterbury.ac.nz> writes: > Actually I gather it had a lot to do with the fact that the Germans > made some blunders in the way they used the Enigma that seriously > compromised its security. There was reportedly a branch of the German > forces that used their Enigmas differently, avoiding those mistakes, > and the British never managed to crack any of their messages. I think you are thinking of the Kriegsmarine (naval) Enigma. Yes they were more careful with procedures, but the machine was also harder to crack because it had four rotors instead of three. IIRC, the Brits were eventually (1942?) able to capture one by shooting up a German submarine and boarding it to get the machine while the sub was sinking; a British sailor wasn't able to get out in time and drowned during that operation. Getting the rotor settings off the captured unit (they may have had to do it more than once) was enough to get a foothold into the code. My memory is hazy on this by now so I may have some parts wrong, but David Kahn's book "Seizing the Enigma" tells the story (I read it many years ago). A fictionalized version appears in Neil Stephenson's novel "Cryptonomicon".
From: Matthew Barnett on 11 Feb 2010 13:24
Paul Rubin wrote: > Gregory Ewing <greg.ewing(a)canterbury.ac.nz> writes: >> Actually I gather it had a lot to do with the fact that the Germans >> made some blunders in the way they used the Enigma that seriously >> compromised its security. There was reportedly a branch of the German >> forces that used their Enigmas differently, avoiding those mistakes, >> and the British never managed to crack any of their messages. > > I think you are thinking of the Kriegsmarine (naval) Enigma. Yes they > were more careful with procedures, but the machine was also harder to > crack because it had four rotors instead of three. IIRC, the Brits were > eventually (1942?) able to capture one by shooting up a German submarine > and boarding it to get the machine while the sub was sinking; a British > sailor wasn't able to get out in time and drowned during that operation. > Getting the rotor settings off the captured unit (they may have had to > do it more than once) was enough to get a foothold into the code. My > memory is hazy on this by now so I may have some parts wrong, but David > Kahn's book "Seizing the Enigma" tells the story (I read it many years > ago). A fictionalized version appears in Neil Stephenson's novel > "Cryptonomicon". U-559? I think that's the one where Hollywood made a film about it, but portraying it as a purely American action. That didn't go down too well in the UK! |