This thread is about discussion of various options to use PGP-variants on Outlook (full version, not express version). The aim is not to discuss whether outlook is good or not. There are other alternatives (thunderbird) with free encryption solutions (enigmail), but they can be discussed in a separate thread. PGP Desktop Home http://www.pgp.com/products/packages/desktop_pro/ Company: Symantec (USA) Price: $99 USD / 91€ OS: Win 2000, XP, Vista & 7 - 32-bit and 64-bit for Vista and 7, others 32-bit Outlook: XP, 2003, 2007 - Express and others also suppoted (not a plugin) Support: PGP/MIME, OpenPGP, S/MIME, X509 v3 Algorithms: AES 256-bit, CAST, TripleDES, IDEA, Twofish, Notes: Difficult to use, not a plugin, but a proxy style encryption/decryption software the sits between the mail client and the server. Industry standard and one of the few with enterprise level support available. GPG4Win http://www.gpg4win.org/ Company: Gpg4win project Price: free OS: Win 2000, XP, Vista & 7 - 32-bit version available (works under 64-bit) Outlook: 2003, 2007 (plugin type) Support: PGP/MIME, OpenPGP, S/MIME, X509 Algorithms: 3DES, CAST5, Blowfish, AES up to 256-bit, Twofish, Camellia up to 256-bit Notes: Perhaps the most hacky and geeky. Has extensive documentation, but not perhaps the first recommendation for newcomers to encrypted mail. cGeep Pro http://www.cgeep.com/features.html Company: SafeLogic (Germany) Price: 70€ OS: Win 2000, XP, Vista & 7 - 32-bit version available (works under 64-bit) Outlook: 2000, XP, 2003, 2007 & separate version for Outlook 2010 (both plugin type) Support: OpenPGP Algorithms: Blowfish, AES 128/192256, CAST, 3DES, up to 4096-bit RSA keys Notes: Perhaps the easiest interface for beginners to learn & use All information is provided as-is (please post corrections, if there are mistakes).