Most file encryptors use methods that rely on the theory of computational security, that is the difficulty of key factorisation prevents decryption ofthe file. But this method may not work forever. It used to be considered that a 56 bit key was unbreakable to brute force attacks, but the government of the USA now requires all Top Secret data to use keys of at least 192 bits. This bar will keep raising as computing power increases. (It is argued by some though that this will never happen due to the laws of physics!) CryptIt is designed to use conventional XOR encryption on keys that are the same size as the file to be encrypted. Furthermore, if you use an unpredictable file that is the same size (or larger) than the original file and you use this file only once, this is known as a one-time pad and it is completely unbreakable, even to computers 1000 years from now. This is because there is no algorithm at all, just a big key, and thus there is no pattern to follow once you have decrypted any part of the file. Thus attempts to decrypt it could result in any file, and there would be no way to verify that it has decrypted correctly. CryptIt can also has some convenience features such as being able to automatically use pad files generated by our program GigAlarm, generate key files (from a stream cipher and thus not best for OTP usage) and also analyse the suitability of your chosen key file.CryptIt also has a ability to use removable media (USB drives, CDs, floppies) as a key code book, further increasing the security and convenience of the method. If your needs are more simpler then you can also use a word (string), but the advantages of the XOR method are lost then. Descriptions can be stored within the encrypted file, as well as the file name of the code. Command line operation is also supported and CryptIt is written in Assembly Language for maximum efficiency.