Toolsley PGPigeon - Simple but powerful OpenPGP-compatible message encryption webapp.
Kleopatra - Kleopatra is a certificate manager and GUI for GnuPG.
DeliverySlip - DeliverySlip helps simplify, secure, and expedite the burdensome elements of online collaboration...
GnuPG - GnuPG is a complete and free implementation of the OpenPGP standard as defined by RFC4880 (also known as PGP).
GPGTools - Use GPG Suite to encrypt, decrypt, sign and verify files or messages.
GPG Suite - Use GPG Suite to encrypt, decrypt, sign and verify files or messages.