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 gpg. gpgv is a stripped down
version of gpg with no encryption functionality, used only to
verify signatures against a trusted keyring. There is also a tool
called gpgsplit to split OpenPGP messages or keyrings into their
component packets. This is mainly useful for seeing how OpenPGP
messages are put together.