Wiki - One Time Pad In cryptography, the one-time pad (OTP) is a type of encryption that is impossible to crack if used correctly. Each bit or character from the plain text is encrypted by a modular addition with a bit or character from a secret random key (or pad) of the same length as the plain text, resulting in a cipher text. If the key is truly random, as large as or greater than the plain text, never reused in whole or part, and kept secret, the cipher text will be impossible to decrypt or break without knowing the key. It has also been proven that any cipher with the perfect secrecy property must use keys with effectively the same requirements as OTP keys. However, practical problems have prevented one-time pads from being widely used. Programming Assignment - Many Time Pad Let us see what goes wrong when a stream cipher key is used more than once. Below are eleven hex-encoded cipher texts that are the result of encrypting eleven plain texts with a stream cipher, all wit