Toolsley PGPigeon!

GnuPG allows to encrypt and sign your data and communication, features a versatile key management system as well as access modules for all kinds of public key directories. GnuPG, also known as GPG, is a command line tool with features for easy integration with other applications. A wealth of frontend applications and libraries are available. Version 2 of GnuPG also provides support for S/MIME.

Gpg4win is an installer package for Windows (2000/XP/2003/Vista) with computer programs and handbooks for email and file encryption. Both relevant cryptography standards are supported, OpenPGP and S/MIME. Gpg4win and the software included with Gpg4win are Free Software (among other things free of charge for all commercial and non-commercial purposes).

GPGTools is an open source initiative to bring OpenPGP to Apple OS X in the form of an easy installer package. This allows you to sign, verify, encrypt, and decrypt files and e-mails. Read the introduction to get a detailed idea of how PGP works.

GPG for Mailis an open source plugin for Apple Mail. Encrypt, decrypt, sign and verify mails using OpenPGP with a few simple clicks.

Outlook Privacy Plugin is a security extension for Outlook 2010. It enables Outlook 2010 to send and receive email messages that are encrypted and/or signed with the OpenPGP standard.

iPGMail is an app that implements the OpenPGP standard (RFC 4880, RFC 6637) and allows the user to create and manage both public and private (RSA, DSA, ECDSA) PGP keys and send and receive PGP encrypted messages.

Desktop Email Encryption provides an end-to-end email encryption solution that automatically encrypts and decrypts email directly from one user's client to another's without the need to log into a third-party website or by other means.

The perfect solution for regulated industries use of email to communicate protected health information (PHI); Paubox email solution is HIPAA compliant and will sign Business Associate Agreements. Great for small to medium sized practices required PHI compliance, but don't have the resources for an expensive IT management and confusing enterprise solution.

A GnuPG Frontend GUI made in C#. It is compatible with PGP as well so it can be a very useful tool for encryption/decryption. It also incorporates a shell extension so it can be easy to right click and decrypt or decrypt.

oPenGP is a solution to support OpenPGP standard (RFC 4880) on your iOS device.