This article is from the PGP FAQ, by Jeff Licquia firstname.lastname@example.org with numerous contributions by others.
PGP has been ported successfully to many different platforms,
including DOS, the Macintosh, OS/2, Unix (just about all flavors),
VMS, the Atari ST, Archimedes, and the Commodore Amiga. A Windows NT
port is reportably in the works as well.
If you don't see your favorite platform above, don't despair! It's
likely that porting PGP to your platform won't be too terribly
difficult, considering all the platforms it has been ported to. Just
ask around to see if there might in fact be a port to your system, and
if not, try it!
PGP's VMS port, by the way, has its own Web page: