Crypto pointer
I'm working on the specs of a new system for work, and I'm trying to figure out how to do authentication/encryption (being the self-appointed crypto guy in the design group). It wasn't until I took a look at how Kerberos does authentication that I figured out something that should work.
I can't post the exact protocol (as that's the property of work) but I'll give a hint:
Don't forget that you can hash the user's password (with, say, SHA-1) and then use that hash to encrypt things—like a session key.