Explanation of One-time Pad

Question

Give a brief explanation of One-time Pad.

Answer 1

The one-time pad, sometimes called the Vernam cipher, uses a string of bits which is generated completely at random. The keystream is same length as the plaintext message and the random string is combined using bitwise exclusive-or with the plaintext to produce the ciphertext. Since the whole keystream is random, the opponent with never-ending computational resources can only guess the plaintext when he sees the ciphertext. Such a cipher is said to provide perfect secrecy and analysis of one-time pad is seen as one of the cornerstones of modern cryptography.