Peter,
Can you give a few places where this is the convention? It seems
counter to what would be intuitive looking at the Microsoft APIs. This
does not mean that you are not correct, I was just wondering.
jim
-----Original Message-----
From: owner-ietf-smime(_at_)mail(_dot_)imc(_dot_)org
[mailto:owner-ietf-smime(_at_)mail(_dot_)imc(_dot_)org] On Behalf Of Peter
Gutmann
Sent: Sunday, October 07, 2001 6:45 PM
To: ietf-smime(_at_)imc(_dot_)org; jimsch(_at_)exmsft(_dot_)com
Subject: Re: Questions on AuthenticatedData
"Jim Schaad" <jimsch(_at_)nwlink(_dot_)com> writes:
1. Should we specify a suggested size for the randomly
generated secret to be
used for HMAC-SHA1? (The size for HMAC-3DES is fixed at the
size of a 3DES
key.)
The convention seems to be to use a 160-bit value (even if
the spec says that
algorithms with variable-length keys use a 128-bit key and
you use that and
then spend half a day trying to figure out why your MACs are
failing when all
the other side tells you is "Bad MAC").
Peter.