Encrypt and sign Gmail messages with FireGPG
Gmail may be an excellent Web-based email application, but there is no easy way to use it with privacy tools like GnuPG. The FireGPG extension for Firefox is designed to solve this problem. It integrates nicely into Gmail's interface and allows you to sign and encrypt not only email messages but also text snippets from any Web page.
As with any other Firefox extension, installing FireGPG is a matter of a few clicks. However, since FireGPG relies on GnuPG, there are a couple of things you have to take care of in order to make FireGPG work properly. First, you have to make sure that GnuPG is installed on your system. You might also want to install a graphical front end to it -- for example, KGpg on (K)Ubuntu -- that you can use to manage keys. Finally, you have to generate the key pair required to encrypt and sign mails and text snippets.
Generating a key pair using KGpg is a straightforward process. Launch KGpg and choose Keys -> Generate Key Pair. In the Key Generation dialog box, enter your name and email address. Select the desired key size; the default 1,024 is strong enough, but stronger keys are also available, if necessary. Next, select the desired algorithm (KGpg supports the RSA and DSA/ElGamal algorithms). Press OK, enter the desired passphrase when prompted, and wait until the utility generates the key pair.