A fast image encryption and authentication scheme based on chaotic maps

In recent years, a variety of chaos-based image cryptosystems have been proposed. The key used for encryption/decryption is usually independent of the plain-image. To achieve a satisfactory level of security, at least two overall rounds of the substitution-diffusion process are required so that a change in any pixels of the plain-image spreads over the whole cipher-image. Moreover, the receiver is not able to determine whether the decrypted image is exactly the one sent. In this paper, a fast image encryption and authentication scheme is proposed. In particular, a keyed hash function is introduced to generate a 128-bit hash value from both the plain-image and the secret hash keys. The hash value plays the role of the key for encryption and decryption while the secret hash keys are used to authenticate the decrypted image. Simulation results show that satisfactory security performance is achieved in only one overall round. The speed efficiency is thus improved.