For those of you who use SIC encryption often (Judges, and others:
'cep message' will send message on your primary SIC encryption. Your primary is the FIRST encryption you add to your account. If you want your primary to be different, you'll have to remove all your keys and re-add them with the one you want first being the first one added.
This makes it easier to send encrypted messages quickly (something NPCs could already do, so I figured PCs should have the ability as well).