Ok, I have been working on this for a while, and I wanted to let you guys have a go at it. I wrote a private key encryption program that I think should be hard to break, I will provide you with the EXE (MS DOS) file, some ciphertext, AND a big chunk of plaintext. The key is not ridiculously large, but it won't be anything obvious so don't bother brute forcing. To encrypt, the program read in some system/time specific info, uses it to encrypt the file along with the key. It then write the system/time specific info to the end of the file encrypted with the key. I THINK that the only weaknesses should be predicitability of the system/time info, or possibly finding patterns in the encrypted values. I dont want to give out any source code yet, but it anyone wants some pieces of it just ask. crackme.zip file with paradox.exe, cipher.txt, and plain.txt -- ___ ___ _____ / \/ \ / \ || | || | || | ||he \_____/row thecrow@iconn.net "It can't rain all the time"