| operating_system = Cross-platform | genre = PGP | license = GNU General Public License | website = gnupg.org }} GNU Privacy Guard (GnuPG or GPG)'s a free software alternative to the PGP suite of cryptographic software. GnuPG's compliant with RFC 4880, which's the current IETF standards track specification of OpenPGP. Current versions of PGP (and Veridis' Filecrypt) are interoperable with GnuPG and other OpenPGP-compliant systems. GPG's a part of the Free Software Foundation's GNU software pro… (More on Gnupg)