Abstract:

In order to overcome the deficiency of the key space of chaotic encryption system and to protect the Data Encryption Standard (DES) algo出hm from being attacked , this paper proposes a secure communication scheme for images by combining the cellular neural network (CNN) with DES algorithm. In the proposed scheme , the original chaotic signal generated by CNN is rounded , taken module , squared , extracted , magnified and excursed. Mter that , a new chaotic pseudo-random sequence is obtained and is used to encrypt the image. Then , the image is encrypted again with DES algorithm. The realization of the secure communication system is also discussed in this paper. Simulated results show that the proposed scheme is of good encηption and decryption efficiency and improves security performance , and that the decrypted results are highly sensitive to the initial condition of CNN and the key of DES. In addition , the traditional cryptanalysis is hardly useful for the proposed encryption system due to the random perturbation in hardware implementation.

Key words: image, secure communication, cellular neural network, chaotic signal, image encryption, Data EncηptionStandard