Introduction
PGP (short for Pretty Good Privacy) is a public key encryption program originally written by Phil Zimmermann in 1991. Over the past few years, PGP has got thousands of adherent supporters all over the globe and has become a de-facto standard for encryption of email on the Internet. If you don't know whether PGP is something for you, please take some time to read Phil Zimmermann's article on why you should use PGP and this document on how PGP works. Adam Back has written this history of PGP.

Platforms
PGP is available for many different platforms, including Windows, Unix, MS-DOS, OS/2, Macintosh, Amiga and Atari.

Latest versions
The latest international freeware versions of PGP are 6.5.1i (Windows 95/98/NT and MacOS only) and 5.0i (other platforms). The older 2.6.3i is still available, but you may experience incompatibility problems if you are communicating with users of PGP 5.0 and later. You can download the most recent versions here. However, there are many other versions of PGP, both freeware and commercial.

Documentation
The PGP documentation is a good starting point. If you have a question about PGP, it is probably answered in one of the many FAQs. A number of PGP books are also available.

Language support
PGP and the PGP User's Guide have been translated into many different languages. There are also a number of non-English PGP resources available on the Web.

Legal stuff
Contrary to what many people seem to think, PGP is perfectly legal to use, provided that you choose the right version and don't download the program from a site in the USA if you're somewhere else in the world.

Other PGP products
PGP is primarily used for encrypting email. PGPfone and PGPdisk are two other products that use PGP encryption technology to secure phone calls and encrypt disk partitions, respectively. The PGP message format has now been standardized through RFC 2440, and in the future we will undoubtedly see many new PGP compatible products.