Gnupg

GnuPG encrypts messages using asymmetric keypairs individually generated by GnuPG users.

GNU, the open-source provider of various utilities including the GnuPG implementation of PGP, implemented a countermeasure on 25 November, the researchers explained.

Before the release of GnuPG 2.0, all releases originated from a single branch; i.e. before November 13, 2006 no multiple release branches were maintained in parallel.

By default, GnuPG uses the CAST5 symmetrical algorithm.

GnuPG also supports symmetric encryption algorithms.

GnuPG does not use patented or otherwise restricted software or algorithms.

In 2003, due to an error in a change to GnuPG intended to make one of those methods more efficient, a security vulnerability was introduced.

Instant messaging applications such as Psi and Fire can automatically secure messages when GnuPG is installed and configured.

Instead, GnuPG uses a variety of other, non-patented algorithms. citation For a long time it did not support the IDEA encryption algorithm used in PGP.

It was in fact possible to use IDEA in GnuPG by downloading a plugin for it, however this might require a license for some uses in countries in which IDEA was patented.

Modern versions of PGP and Veridis' Filecrypt are interoperable with GnuPG and other OpenPGP -compliant systems.

Software applications such as GnuPG or PGP can be used to encrypt data files and Email.

Support for this method has been removed from GnuPG versions released after this discovery (1.2.4 and later).

Support of IDEA is intended "to get rid of all the questions from folks either trying to decrypt old data or migrating keys from PGP to GnuPG", citation and hence is not recommended for regular use.

The Free Software Foundation has developed its own OpenPGP-compliant program called GNU Privacy Guard (abbreviated GnuPG or GPG).