Peter,
The major issue seems to be whether the "corporate key" feature is a valid
S/MIME requirement. I believe that issue needs to be debated further on the
list. The WorldTalk folks believe that this is a valid requirement. Does
anybody else believe that it is?
If the S/MIME WG agrees that this is a valid requirement, then I believe
that it should be implemented via an extension in each user's cert. This is
the most secure method because the CA's signature of the cert tightly binds
the identity of the "corporate key" cert with the user's key material and
identity. Any other method is less tightly linked and presents
opportunities for attackers to spoof the originator into creating
recipientInfos for entities' certs other than the intended recipient's cert
and (if required) the intended recipient's "corporate key" cert.
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John Pawling
jsp(_at_)jgvandyke(_dot_)com
J.G. Van Dyke & Associates, Inc.
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