imitation game movie

[Jon Elson]

On 02/10/2015 12:31 PM, Noel Chiappa wrote:
>      > From: Jon Elson
>
>      > such as to not evacuate Coventry when they knew it was next for getting
>      > blitzed.
>
> Ah, this is alas an urban legend ('bogo-meme', to coin a nice neologism);
> started, IIRC, by Winterbotham.
OK, thanks for clearing that up.  I didn't know.
>
>
>      > there are some descriptions that the actual wiring of the rotors was
>      > done AT Bletchley
>
> I'd love to read about that - do you know/recall where you saw it?
Ugh, I've been reading up on this stuff for more than a 
year, now, and did not keep
links.
>
>      > If a German spy was to get his hands on the drawings for even one
>      > (wired) rotor, they would have realized how thoroughly the British had
>      > penetrated the Enigma system
>
> I am less certain of this. I seem to recall (alas, too busy to look it up,
> unless someone's really interested) that the Germans had something of a
> modern concept of code security, where it's assumed that the actual ciphering
> machine is compromised, and security depends on the security of the keys.
>
> Given the wide deployment of Enigma at the tactical level, the odds were good
> that the machine itself had been compromised. So for them to have found out
> that the British had the rotor wiring would not have been a big surprise, I
> would expect.
Yes, but they might assume the Brits were just using 
hand-operated copies of Enigma to
try to decode one message at a time.  If they had an idea of 
the scale of the Bombe machines,
and some of the tricks the B.P. guys were exploiting, they 
would have realized
the Enigma was badly compromised.
> However, had they gotten any kind of detailed description of the Bombe, it
> would have not been that hard to work out that its use was to break into
> Enigma. In that sense, the Bombe's overall design was in fact a bigger secret
> than the fact that they had the rotor wiring.
Yes, for sure.
> And of course as a result of the XX system, the British were fairly sure that
> there were no German spies in the UK at the time, anyway.
>
The XX system??  What's that?

Jon