GnuPG is a complete and free implementation of the OpenPGP standard as defined by RFC4880 (also known as PGP). GnuPG allows to encrypt and sign your data and communication, features a versatile key management system as well as access modules for all kinds of public key directories. GnuPG, also known as GPG, is a command line tool with features for easy integration with other applications. A wealth of frontend applications and libraries are available. Version 2 of GnuPG also provides support for S/MIME and Secure Shell (ssh).
GnuPG is Free Software (meaning that it respects your freedom). It can be freely used, modified and distributed under the terms of the GNU General Public License .
GnuPG comes in three flavours:
2.0.29 is the stable version suggested for most users,
2.1.8 is the brand-new modern version with support for ECC and many other new features,
and 1.4.19 is the classic portable version.
Project Gpg4win provides a Windows version of GnuPG stable. It is nicely integrated into an installer and features several frontends as well as English and German manuals.
Reconquer your privacy
Even if you have nothing to hide, using encryption helps protect the privacy of people you communicate with, and makes life difficult for bulk surveillance systems. If you do have something important to hide, you are in good company; GnuPG is one of the tools that Edward Snowden used to uncover his secrets about the NSA.
Please visit the Email Self-Defense site to learn how and why you should use GnuPG for your electronic communication. If you need printed leaflets check out FSFE’s GnuPG leaflet.