Cellular automata are dynamical systems, discrete in terms of both space and time. Many cellular automata are capable of generating chaos and are well suited for applications like digital image encryption and scrambling. Various cellular automata-based digital image scrambling techniques have been proposed in literature. An adversary may have access to a set of images from which the particular image is scrambled. The problem with these techniques in this particular case is that an adversary may be able to find out the true content of the scrambled image just by comparing its histogram with the histograms of a suspected set of images. In this paper, a secure digital image encryption technique based on outer totalistic cellular automata is proposed that modifies the histogram of the scrambled image so that it is difficult to guess the true content carried in the digital image.
In order to improve the capability of scrambling encryption and anti-aggressive, we extended the two-dimensional Arnold transformation to three-dimensional, and designed one kind of new diffusion equation of the digital image pixel gray value, then introduced a novel digital image encryption algorithm based on them. The large number of simulation results and analysis have both shown that the proposed scheme is a very effective encryption algorithm.
An Image Scrambling Encryption Algorithm
