GnuPG - The GNU Privacy Guard suite of programs
GnuPG is a set of programs for public key encryption and digital signatures. The
program most users will want to use is the OpenPGP command line tool, named
gpg2. gpgvis a stripped down version of gpg2 with no
encryption functionality, used only to verify signatures against a trusted
keyring. gpgsm is the X.509/CMS (for S/MIME) counterpart of
gpg2. gpg-agent is a passphrase and private key daemon which may
also emulate the ssh-agent.
gpg(1), gpg2(1), gpgv(1), gpgsm(1),
gpg-agent(1), dirmngr(8), scdaemon(1)
The full documentation for this tool is maintained as a Texinfo
manual. If GnuPG and the info program are properly installed at your site,
should give you access to the complete manual including a menu
structure and an index.