Riordan's Internet Privacy Enhanced Mail
RIPEM

    (RIPEM) A (not yet complete, but useful)
   implementation of Privacy Enhanced Mail (PEM).  RIPEM allows
   your electronic mail to have the four security facilities
   provided by PEM: disclosure protection (optional),
   originator authenticity, message integrity measures and
   non-repudiation of origin (always).

   RIPEM was written primarily by Mark Riordan
   .  Most of the code is in the public
   domain, except for the RSA routines, which are a library
   called RSAREF licensed from RSA Data Security, Inc.

   The current (November 1993) version of RIPEM is 1.1a; the
   current version of the Macintosh port of RIPEM is 0.8b1.

   (1998-07-03)