Re: DES & IBM's patents

EKR (ekr@terisa.com)
24 Jul 1998 12:52:40 -0700

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"John Kelsey" <kelsey@plnet.net> writes:
> Actually, I believe CDMF is just a specific way to choose a DES key,
> which has 40 bits of strength but doesn't have some subset of its
> bits always set to zero. I don't believe CDMF does anything weird to
> the DES key schedule internals.
CDMF is basically a key pre-processor. It provides a function that takes
as input a DES key and outputs another DES key with 40 bits of
entropy. That key is then used for DES.

I.e.
CDMF(K,MSG)=DES(F(K),MSG)

-Ekr

-- 
[Eric Rescorla                             Terisa Systems, Inc.]
		"Put it in the top slot."

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