I'm looking for a resource which can offer advice on generating unique ID or
registration codes. We're preparing to distribute a large number of
CD-ROMs, and we want each one to have a unique code that we can print on
that disc's sleeve. Kind of like when AOL sends you a CD in the mail, it's
got a unique login code printed on it. (we're not talking about shareware
reg. or unlock codes)

I'm looking for both software that can generate ID's, but I'm even more
interested in any articles or whitepapers that discuss the theory behind
generating good ID's... severely reducing the likelihood of repetition or
guessing without making it too difficult for the user.

We considered using GUIDs but decided they were too long to expect the user
to enter correctly, and also, consecutively-generated GUID's had only one
character difference, giving a savvy user a good chance to guess another
GUID based on the one he/she has.

If anyone can help by referring me to a good resource that covers this
stuff, I'd really appreciate it!!

Andy Goldberg