GNU Privacy Guard, also called GnuPG or GPG for short, is an alternative to the PGP suite of encryption software. The Free Software Foundation includes GPG in its GNU software project. GPG is compliant with RFC 4880, the IETF (Internet Engineering Task Force) standards specification for OpenPGP. It receives funding from around the world, including a large portion from the German government.
The production version of GPG was first released on September 7, 1999, and developed by Werner Koch. It was ported to the Windows operating system in 2000. The basic version of GPG features a command line interface, but there are front-end applications that provide users with a graphical user interface for GPG.