Enhanced Audio Cryptosystem Using Multiple Secret Keys and Permutations in Time and Transform Domains

This paper presents an enhanced audio speech cryptosystem based on three enhancements for permutation and substitution of speech segments using multiple secret keys and permutations in time and transform domains. The first enhancement method is based on repeating the first and last permutation steps in both encryption/decryption procedures for several times to enhance the security level. The second and third enhancement methods are based on...