Digitally signing a message helps ensure it has not been tampered with (providing integrity) while encrypting a message helps ensure that nobody, except the intended recipient(s), will be able to “see” the message while in transit on the network (provides confidentiality).
Mozilla supports PGP/GPG with the aid of the mozilla-enigmail package, so make sure you install it first, along with the gnupg package before trying to send secure messages.
GPG keys can also be generated within Mozilla by choosing + from the menu (Figure 10.12). Fill in the Passphrase and Passphrase (repeat) fields with a secret pass-phrase, the Comment field with any string to identify you, and click on the button.
After clicking on the button, try to make your system perform disk-intensive operations (like actively browsing the web) to increase the “randomness pool” and speed-up key generation.
It is highly recommended that you publish your public key on specialized servers, for example KeyServer. This way your friends can get your key from there and you can enjoy digital signature and message encryption features.
The following table summarizes the new buttons Enigmail adds and a brief explanation of their functions.
Table 10.3. Enigmail Toolbar Buttons