[67256] in Cypherpunks
DESCrack keyspace partitioning
daemon@ATHENA.MIT.EDU (geeman@best.com)
Fri Oct 4 06:20:44 1996
From: "geeman@best.com" <geeman@best.com>
To: "'cypherpunks@toad.com'" <cypherpunks@toad.com>
Date: Thu, 3 Oct 1996 19:48:36 -0700
What about the heuristics of partitioning the keyspace?
Seems to me that a _subset_ of all possible keys is much more likely
to appear than a random selection from an equidistributed population 0..2^56.
(P)RNG's just aren't that likely to produce a key of 010101010.....
nor 001100110011... etc etc and I have been thinking about how one might formalize
and exploit this randomness property to increase the probability of finding the key sooner.
So a keysearch strategy should be something other than a partitioning of 2^26 into N bins
with a linear search within each bin. I realize that it is POSSIBLE that a key of 1010101010...
was used, (excluding weak keys from consideration) ---- but I have seen "certifiable" RNG's and,
God Bless 'em, they just dont ever produce anything with any predictability.
Is not the lack of predictability a predictable, and therefore exploitable, attribute?
Any thoughts here?
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