Internet text mail has been developing to satisfy various user
requests, such as transporting non-textual objects and privacy
enhancements. While MIME redefined the mail body format to support
non-textual objects and multipart structure, PGP provides encryption
and digital signature features for text mail. MIME, however, does not
provide privacy services whereas non-textual objects cannot be
exchanged with PGP. It is of recent interest to integrate PGP and MIME
so that users can make use of these two services at the same time. 
This paper describes an integration of PGP and MIME. Our scheme embeds
PGP objects into MIME and maintains backward compatibility with PGP. 
It is possible to encrypt, sign, and sign-then-encrypt non-textual
objects, singleparts in a multipart, an entire multipart, etc. We
also explain our viewing and composing mechanisms that allow users to
handle PGP/MIME messages intuitively without format restrictions.