As has been publicized recently, computer networks are quite susceptible to eavesdropping. For example, electronic mail messages are similar to traditional postcards in that postmasters and others can read them while they're on their way to their destination.

PGP (Pretty Good Privacy) is a software package that enhances the privacy of information using cryptography. One of its major uses is to encrypt email so that only the intended recipient(s) can decipher the content. It can also be used to verify that a message came from who it says it's from, and to encrypt local files.

PGP runs on PCs, Macs, and UNIX and messages are interchangable among all the platforms.

International PGP Home Page
The latest versions of PGP
MIT PGP download page
PGP for other operating systems