Hopefully, our resident cryptography expert Jez Smith will chime in soon, but in the meantime...

I assume, by "Bruce", you mean Bruce Schneier. Did you simply find the DES code on the 'net, or do you also have access to his book "Applied Cryptography"? I have found that book to be helpful in organizing my thinking about what exactly I'm trying to accomplish by using cryptography (i.e., what kinds of attacks I'm protecting against), the appropriate level of security necessary for my requirements, and thus the appropriate cryptographic technique.

I have used stream ciphers using linear feedback shift registers on some occasions. They are easy to implement with very little code. The stream cipher could be what you are referring to by the "XOR rotate key", in which case, I'm sorry for telling you what you already know.