Talks about using multipart/signed and multipart/encrypted for
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Unfortunately, the key reference doesn't seem to be an RFC after all:
[7] James Galvin, Sandy Murphy, Steve Crocker, and Ned Freed. Security
Multiparts for MIME: Multipart/Signed and Multipart/Encrypted.
RFC XXXX, Trusted Information Systems and Innosoft, XXXX 1994.
so I'm puzzled as to where this reference might be. I didn't see an
obvious internet draft with that as the title, either.