Image Encryption Algorithm Based on Synchronized Parallel Diffusion and New Combinations of 1D Discrete Maps

Abstract

The need for secure communications has triggered research in cryptography in general and image encryption in particular. Papers have been published and many approaches used. One of them is chaos-based image encryption which uses a chaotic map as an essential part of the cryptosystem. For the cryptosystem to be efficient, the chaotic map must exhibit a good chaocity. Hence the need to propose a good chaos generator. In this paper, we set forth a general approach to design a chaotic generator with good properties, using the existing ones. This method was applied and a chaotic map generator obtained. Then an encryption algorithm into which the above chaotic map was combined to the image characteristics, to generate both the encryption keys and the random numbers needed for the encryption process. The encryption procedure consisted in a diffusion process in cipher-block-chaining mode of block image synchronized for parallel computing, followed by a confusion process implemented by means of pixel permutation. The security and robustness tests carried out on the algorithm yielded a high sensitivity to any pixel change or key change and robustness in face of statistical, differential, Chosen known plain /cipher test attacks combined to a fast encryption speed allowing real-time operations.