If Cynthia wanted to send very sensitive information to James, she'd encrypt the email message. After typing it, she puts her cursor in the body of the email, hits Ctrl+A followed by Ctrl+Shift+C. The software asks her to select the keys to which the message will be encrypted. It has already selected her own key by default.

After entering her passphrase, the message is encrypted. When it reaches James, all he sees is alphabet soup.

Curious as to what he's supposed to "note," James puts his cursor into the message window and hits Ctrl+Shift+D, then enters his passphrase. The message is decrypted.

Next: Using PGP Key Servers