PrivateMail for Gmail
PrivateMail for Gmail is an extension that makes it easy to send and receive encrypted emails using mail.google.com. After a quick and easy setup, you will be ready to send PGP encrypted emails. After that, all you need to send an encrypted email is the recipient’s public PGP encryption key. If the recipient doesn't have a PGP encryption key, it’s no problem, PrivateMail lets you invite the recipient to PrivateMail. Once they accept the invitation, you will automatically have their newly created PGP encryption key, and they will have yours. All you need to do to send an encrypted email is write your email as normal, then click the "Encrypt" button. After that, you will see your message replaced with the encrypted version of the message you typed. Now, the only person who can view the original, unencrypted message text is the recipient. Finally, click send as you normally would, and your email will be sent. Decrypting a message that was sent to you is also easy. When you click on an email that was encrypted using PGP, PrivateMail will try to automatically decrypt the message. If the automatic decryption does not work, then you can always click the "Decrypt" button to force the message to be decrypted if it was formed properly.