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Re: Clipper III on the table
At 02:44 PM 10/1/96 -0400, Perry wrote:
>We really have to work on cracking DES at least once -- it would
>substantially reduce the wind in the Administration's sails.
56 bits + GAK does generally mean DES/GAK, though RC4/56/GAK is also possible.
One "56-bit" protocol that might be allowable under the new rules is
"something strong with all but 56 key bits revealed", e.g. RC4/128
with 72 bits salt revealed (like the RC4/128 with 88 bits salt revealed that
Netscape uses, or 3-DES with 112 bits salt revealed), which would be
substantially stronger against cracking than raw 56-bit DES.
A big advantage is that it makes pre-computation of lists less useful,
since two cyphertexts with the same 56-bit key might be different in the
top N-56 bits of key, and the key schedules are less reusable.
The 3DES version, for instance, also gains because some of the big
DES hooks that let you scrounge a few bits don't work.
# Thanks; Bill
# Bill Stewart, +1-415-442-2215 [email protected]
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