ANN: obfuscate

[Paul Rubin]

Gregory Ewing <greg.ewing at 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".