This post will discuss configuring and using the open-source software, GNU Privacy Guard or GnuPG as it is frequently listed. All other applications and plug-ins referenced require GNU Privacy Guard. I have listed some applications and plug-ins that are available including those that I use. There are GUI as well as command-line based applications available.
GNU Privacy Guard
GnuPG comes in two flavors: 1.4.9 is the well known and portable standalone version, whereas 2.0.12 is the enhanced and somewhat harder to build version.
On the Mac I am running 2.0.12 since there was a binary available. I am running 1.4.9 on Windows since I did not see a 2.0.12 binary available, but 1.4.9 meets my needs.
Email Clients
Apple Mail
Use Sen:te GPGMail which is GPGMail is a plug-in for Apple's Mail, providing a front-end to GnuPG for some operations. It allows you to read/write encrypted messages, as well as electronically signed messages. A quote from the site "GPGMail is a complete hack, relying on Mail's private internal API." So with major updates to OS X/Mail you may need a new version of GPGMail.
GPGMail is released under the BSD License. The author, Stephane Corthesy has asked that if you enjoy the product you send him a postcard!
Thunderbird
Thunderbird open source Email client
Enigmail is a security extension to Mozilla Thunderbird and Seamonkey. It integrates the renowned OpenPGP standard provided by GnuPG.
Set owner trust after import otherwise it may not work.
Outlook and Outlook Express
Since Microsoft Outlook and Outlook Express do not allow third party software access to the raw MIME headers, they do not work well with PGP/MIME mail. They do work fine with GnuPG when receiving message that use inline encoding i.e. no attachments. But for the love of God ditch Outlook!
WinPT is a graphical user front-end for the free OpenPGP implementation GnuPG.
Some Settings I Used
2048 bit key
wwwkeys.pgp.net key server. I had used ldap://keyserver.pgp.com at first but my test client on Windows could not locate me! So after some trials I switched to using wwwkeys.pgp.net and it came right up.
Folks that want to encrypt something they are sending to you need your public key. So your public key is used to encrypt their email to you. If you get confused as to what key to share remember this phrase from object-oriented software engineering: Friends don't show their friends their private parts :-)
