I have a simple example of how to do simple xor encryption using no external headers (except stdio.h and strings.h) on my webpage (under the programming section at:

http://www25.brinkster.com/cheeseball

I haven't gotten hardly any of my programs up yet...but I have the source of a few things (a IPsec client/server, and stuff like that) that I used an extended example of this in, but haven't posted them up yet. Just thought I would post it in case someone needs a raw example of how to do it.