Pretty Good Privacy

Pretty Good Privacy (PGP) is a computer program that provides cryptographic and authentication. PGP is often used for signing, encrypting and decrypting electronic mails (e-mails) to increase the security of e-mail communications. It was originally created by Phil Zimmermann in 1991.
PGP and other similar products follow the OpenPGP standard () for encrypting and decrypting data.
OpenPGP.
OpenPGP is on the Internet Standards Track; the current specification is (November 2007). OpenPGP is still under development and the successor to , which is , has been made a proposed standard. Many e-mail clients provide "OpenPGP-compliant" email security as described in .
The Free Software Foundation has developed its own "OpenPGP-compliant" program called GNU Privacy Guard (abbreviated GnuPG or GPG). GnuPG is freely available together with all source code under the GNU General Public License (GPL) and is maintained separately faraway from several Graphical User Interfaces (GUIs) that interact with the GnuPG library for encryption, decryption and signing functions (see KGPG, Seahorse, MacGPG). Several other vendors have also developed "OpenPGP-compliant" software.