GnuPG and PGP are public key encryption programs, they are nice and convenient and helpful at avoiding sending ‘important’ content in the clear in email (SMTP is plain-text you remember, right?) Often console-based email clients can be fussy to setup to use this software. Here’s a quick guide, stolen from someone else (Stolen-content).
Once you make your new kernel, how do you put it into use?
Often when you start with an SSL certificate it has a passphrase, you may want to change that later. You may realize your webserver won’t start without entering a passphrase at the startup dialog. That’d be a bad thing for your webserver, eh? Really the problem isn’t with the certificate so much as the key, which is encrypted with a passphrase.