Re:WWII Bombe operator Ruth Bourne: I'd never heard of Enigm...
by qubex on Wednesday September 26, 2018 @03:17AM
(#18073489)
GCHQ and it’s American counterparts were more interested in deceiving the Soviets into believing that they hadn’t been able to break a type of cipher unrelated to Enigma, namely the pseudo-Vernam Ciphers as embodied by Tunny/Lorenz/* Geheimschreiber* for transmitting stream-enciphered teleprinter traffic (as decoded by Colossus). Enigma was trivial by comparison and it’s insecurity was known to the USSR.
Not to mention any units captured by the Soviets - GCHQ wanted to make sure any use of the units by them would be decryptable as well.