So far in this thread, two methods of encrypting headers have been
discussed: encapsulating a complete message in a message/rfc822 and
encapsulating an SMTP session in BSMTP. Both can be used for end-to-end
encryption and the first probably inter-operates quite well amongst
existing PGP/MIME or S/MIME clients.
at this point, i'd like to see the methods mentioned/referred to in
some specification so i can point mail client developers at such a
document for the purposes of having them work on implementations that
will interoperate.
I don't see what any of this has to do with OpenPGP. Modifying SMTP
is clearly out of our scope, and message/rfc822 is already defined in
the MIME spec. We don't have anything to do with this, and IMO this
discussion should be transferred elsewhere.
Hal Finney