A protocol to encrypt digital images using chaotic maps and memory cellular automata
A. Martı́n del Rey, G. R. Sanchez, Agustín de la Villa Cuenca · Logic Journal of IGPL · 2015
In this article a novel encryption scheme for RGB digital images is introduced. The proposed protocol consists of two iterative phases: the confusion phase ruled by the 2D chaotic Cat map, and the diffusion phase governed by a reversible memory cellular automata over F28. This algorithm is shown to be secure against the more important cryptanalytic attacks on image encryption methods (statistical attacks, sensitivity dependence, differential attack, etc). More specifically, it is shown that: (i) the correlation coefficient of two adjacent pixels (horizontal, vertical and diagonal adjacency) of the encrypted image is approximately k·10−3, whereas the same parameter for the original image is near 0.99; (ii) approximately the 99.5% of pixels of the encrypted image are changed when only one bit of the secret key is modified; (iii) the NPCR coefficient of the encrypted image if near 99.6%, and the UACI coefficient is about 33.3%. Moreover, it supposes an improvement of the CA-based methods to encrypt digital images using chaotic maps.