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.