What you are talking about sounds like the original Vernam cipher that Dave Kahn talks about in _CodeBreakers_. There, he was using a teletype with two XORing tapes. One tape was 1000 characters long, the other was 999. Thus, 999000 characters would have to go past before the system repeated. HOWEVER, once it does repeat, all security is compromized. Even before that time, I believe there are subtle attacks you can use based on the repetition of the keys. So, this is not a secure cipher method. I would personally suggest tacking an 128 bit IDEA key onto 4dos.com instead. Or use DES even. BTW: Though you could come up with a 30Kb+ string which when XORed would give you any plaintext, you could not come up with a few small strings which when used over each other would give you that. There just isn't enough information to make that possible. -- PGP 2.3 Key by finger