[Cryptography] Imitation Game: Can Enigma/Tunney be Fixed?
bear at sonic.net
Wed Jan 7 15:23:46 EST 2015
On 01/07/2015 10:11 AM, Phillip Hallam-Baker wrote:
> That is my understanding as well. It took me a long time to work out what
> the steckering did because I could not really see what the point was. They
> could have achieved a lot more bang for the buck if the steckering had some
> sort of interaction with the reflector. As it was they just had two
> orthogonal ciphers, a rotor cipher and a Ceasar cipher that was easily
> stripped off with a meet in the middle approach.
Steckering at the reflector end would have been much more effective
because that would have decorrelated the permutation between input
and reflector from the permutation between reflector and output.
The cyclometric attack wouldn't have worked at all, for example.
But that's relatively subtle math, and I think it's mostly something
that cryptographers have all learned since. It's easy to understand
someone in WWII failing to realize that.
> In addition to what Jon raised, one of the biggest operational defects was
> the habit of sending out 'test' messages of a single letter repeated. that
> combined with the reflector no letter maps to itself defect made it really
> easy to spot cribs.
In reviewing the Third Reich's operational record with Enigma,
it's hard to tell whether they lost the war because of sheer
stupid arrogance (with the failures of training, overconfidence
in equipment and procedures, and systematic underestimation of
opponents that implies), or whether it just seems that way now
because we have the record of the cryptanalytical progress against
Enigma which depended so much on those mistakes.
Does every large-scale military organization make stupid mistakes
subordinating security to petty officiousness, redundant procedure,
personal ego, and just plain laziness? Is this level of
operational failure something that people need to design for
if building systems for military clients?
I suppose a review would require gathering data about how often
warrant officers (those who have a warrant on account of expertise
with some particular crucial field) are overruled by commissioned
officers (those who are in the chain of command and have
commissions on account of military training). Seriously, part
of good military training ought to be a realistic assessment of
how much to trust nonmilitary training.
I mean, imagine a warrant officer cryptography clerk, saying to
Herman Goering: "Sir, it degrades operational security to repeat
this same greeting word-for-word with full honorifics etc, at the
beginning of each message...." Odds of him getting overridden?
Odds of him being too afraid to even speak up in the first place
even though he knows it to be true? Odds of him getting punished
for telling the truth?
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