[67285] in Cypherpunks
Re: DESCrack keyspace partitioning
daemon@ATHENA.MIT.EDU (Mike McNally)
Fri Oct 4 09:30:13 1996
Date: Fri, 04 Oct 1996 08:10:29 -0500
From: Mike McNally <m5@tivoli.com>
Reply-To: m5@tivoli.com
To: "geeman@best.com" <geeman@best.com>
Cc: "'cypherpunks@toad.com'" <cypherpunks@toad.com>
geeman@best.com wrote:
>
> (P)RNG's just aren't that likely to produce a key of 010101010.....
> nor 001100110011... etc etc
Right. A good CSPRNG is ulikely to produce the pattern 010101010101.
It's also unlikely to produce the pattern 0011001100110011. Oh, and
it's also unlikely to produce 01100100101001011. In fact, a good
32-bit CSPRNG has only a 1/2^32 chance of producing any particular
bit pattern. Of course, another way of saying that is that it's just
as likely to get an "obvious" bit pattern as it is to get any other
one. You can't just throw away part of the keyspace based on such
bogus reasoning. (There may be other reasons to throw away part of
the keyspace, of course.)
______c_________________________________________________________________
Mike M Nally * IBM % Tivoli * Austin TX * How quickly we forget that
mailto:m5@tivoli.com mailto:m101@io.com * "deer processing" and "data
http://www.io.com/~m101/ * processing" are different!
