BREAKING A CHAOTIC CRYPTOGRAPHIC SCHEME BASED ON COMPOSITION MAPS

Abstract

Recently a chaotic cryptographic scheme based on composition maps was proposed. This paper studies the security of the scheme and reports the following problems: (1) the scheme can be broken by a differential attack with 6 + ⌈ log L (MN)⌉ chosen plaintexts, where MN is the size of the plaintext and L is the number of different elements in plaintext; (2)the two composition maps both do not work as a secure and efficient source of random numbers; (3)the scheme is not sensitive to the changes of the plaintext.