S/MIME

[Dan Weinreb <dlw@exceloncorp.com>]

Chris, in mail some time ago, you said:

   Transient confidentiality may be provided at the transport level using
   TLS (SSL), IPSEC or other similar mechanisms which provide for encryption
   on the wire. S/MIME may be used to provide for persistent confidentiality
   of the payload object(s).

Is it really OK to use S/MIME in this way?  The MS spec doesn't seem
to say anything about S/MIME.

I have not yet gotten up to speed on S/MIME (so many RFC's, so little
time) but would we have to specify something about how the key
exchange is done, analogously to the initial negotiation in TLS?
There would have to be some way to tell the MSH the avlue of the
private key and corresponding certificate, no?  I don't really
know the details, but it seems that if we want to allow S/MIME,
we have to do more than just say "yes, go ahead, use S/MIME"...

Thanks.
-- Dan