Robert, see below
$ pgp -h
Pretty Good Privacy(tm) Version 6.5.8
$ uname -a
HP-UX mkifmgr2 B.11.11 U 9000/800 151424690 unlimited-user license
I got it from http://web.mit.edu/network/pgp.html (MIT PGP distribution site) which apparently no longer provides it.
This site http://www.pgpi.org/products/pgp/versions/freeware/unix/ seems to have it.
