Encrypting a short string?

[Paul Rubin]

erikcw <erikwickstrom at gmail.com> writes:
> In essence what I'm doing is trying to manage tickets for a helpdesk.
> I want the ticket identifier to be short enough to fit in the subject
> line along with the normal subject chosen by the user. 

I think you should use a database to maintain the email addresses
since you already have to maintain the contents and history of the
help ticket anyway.  If the contents of the database is private, then
assign the ticket numbers in an unpredictable sequence--I can tell you
how to do that cryptographically if you want (I've posted code for it
a few times before).  That is to stop users from guessing ticket
numbers that are valid but belong to other users.  If it's a public
database (e.g. a bug tracker for a free software project) or if
accessing a particular ticket needs a user credential associated with
that ticket, then you may as well use sequential numbers.