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Old 25th May 2020, 12:26 pm   #13
greg_simons
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Join Date: Jul 2004
Location: Evesham, Worcestershire, UK.
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Default Re: Code-Breakers:Bletchley Park's Lost Heroes

Quote:
Originally Posted by RogerEvans View Post
If you want to know more about details of the tunny code breaking effort and Colossus internals then I can recommend the book 'Colossus' by Jack Copeland and others. Astonishing details including how Bill Tutte deduced the SZ42 internals, the extreme reliability of the (I think EF50s) in Colossus and the tiny differences from randomness in the teleprinter code that had to be exploited to get the initial wheel settings. And it was all only possible because of the catastrophic error of procedure in the two messages that Craig referred to which were not only sent with the same initial wheel settings, but in the early days of the SZ42 some of the initial wheel settings were sent in plain text at the start of the message. The buterflies wings ...!

Roger
Yes indeed roger, we must be eternally grateful not only to the brilliant minds at the park but also to the unintended sloppiness of some german signals operators who gave our codebreakers something to latch onto that helped the decoding process along.
Greg.
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