GnuPG

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.

Free Open Source Mac OS X Linux Xfce OpenPGP

Enigmail

enigmail is a security extension to mozilla thunderbird and seamonkey. it enables you to write and receive email messages signed and/or encrypted with the openpgp standard.

Free Open Source Mac OS X Windows Linux Thunderbird SeaMonkey GnuPG

OpenKeychain

OpenKeychain helps you communicate more privately and securely.

Free Open Source Android Android Tablet K-9 Mail

GPGMail

gpgmail is an open source plugin for apple mail. it brings the functionality to sign, verify, encrypt and decrypt mails using the openpgp standard.

Free Open Source Mac OS X GPGTools

GPG Suite

gpg for mail is an open source plugin for apple mail. encrypt, decrypt, sign and verify mails using openpgp with a few simple clicks. gpg keychain is an open source application for mac os x.

Free Open Source Mac OS X GnuPG

Kleopatra

Kleopatra is a certificate manager and GUI for GnuPG. The software stores your OpenPGP certificates and keys.

Free Open Source Windows Linux GnuPG

WebPG

webpg is a free, open source suite of tools to bring openpgp (gnupg/pgp, gpg, gnupg) to the browser, in an effort to make...

Free Open Source Mac OS X Windows Linux Chrome Thunderbird

iGPMail

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...

Commercial

OneTime

OneTime is an open source encryption program that uses the one-time pad algorithm to allow two parties to communicate privately. It has features to assist with the...

Free Open Source Mac OS X Windows Linux

oPenGP

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

Commercial

Ciphermail for Android

CipherMail for Android is an Android application which can be used with your existing Android mail application to send and receive S/MIME digitally signed and encrypted...

Free Android S/MIME