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 itself is a commandline tool without any graphical stuff. It is the real crypto engine which can be used directly from a command prompt, from shell scripts or by other programs. Therefore it can be considered as a backend for other applications.
However, even when used on the command line it provides all functionality needed - this includes an interactive menu system. The set of commands of this tool will always be a superset of those provided by any frontends.
- Full replacement of PGP.
- Does not use any patented algorithms.
- GPLed, written from scratch.
- Can be used as a filter program.
- Full OpenPGP implementation (see RFC4880 at RFC Editor).
- Better functionality than PGP and some security enhancements over PGP 2.
- Decrypts and verifies PGP 5, 6 and 7 messages.
- Supports ElGamal, DSA, RSA, AES, 3DES, Blowfish, Twofish, CAST5, MD5, SHA-1, RIPE-MD-160 and TIGER.
- Easy implementation of new algorithms using extension modules.
- The User ID is forced to be in a standard format.
- Supports key and signature expiration dates.
- English, Danish, Dutch, Esperanto, Estonian, French, German, Japanese, Italian, Polish, Portuguese (Brazilian), Portuguese (Portuguese), Russian, Spanish, Swedish and Turkish language support.
- Online help system.
- Optional anonymous message receivers.
- Integrated support for HKP keyservers (wwwkeys.pgp.net).
- Clears signed patch files which can still be processed by patch.
- and many more things….