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.
Digital Image Scrambling Using 2D Cellular Automata