You might want to take a look at draft-ietf-impp-msgfmt-??.txt (please
forgive me for not knowing the current revision number). This draft
tries to describe a MIME format for encapsulating a MIME message with
it's associated meta-content (header information). The purpose of
this draft was to allow a sender to sign a message and associated
message headers, and then allow a transport system to send the message
from the sender to the recipient(s).
Using MSGFMT does imply some duplication of headers if your transport
system requires them (e.g. IMPP, SMTP, etc). But if you don't need
the transport-layer headers, you can stuff them into the MSGFMT part
and sign them. Unfortunately this would be an incompatible change
with the current netnews protocols.
But I figured I'd point out that there are efforts to try to unify the
message/message-meta-data dichotomy.
Enjoy!
-derek
--
Derek Atkins, SB '93 MIT EE, SM '95 MIT Media Laboratory
Member, MIT Student Information Processing Board (SIPB)
URL: http://web.mit.edu/warlord/ PP-ASEL-IA N1NWH
warlord(_at_)MIT(_dot_)EDU PGP key available