PGP (Pretty Good Privacy) is a public key encryption pack-
age to protect E-mail and data files.  It lets you  commu-
nicate  securely  with  people  you've  never met, with no
secure channels needed for prior exchange of  keys.   It's
well featured and fast, with sophisticated key management,
digital signatures, data compression, and  good  ergonomic
design.

WWW: http://www.pgpi.org/