A new set of image encryption algorithms based on discrete orthogonal moments and Chaos theory

In this paper, we introduce a new set of image encryption algorithms based on orthogonal discrete moments and chaos. Two logisitic maps are used to confuse and diffuse the moments’ coefficients obtained using: Tchebichef, Krawtchouk, Hahn, dual Hahn and Racah. An external key of 128 bits is used as the encryption key, some mathematical operations are performed on the key to adapt it as the initial conditions of the logisitic maps. Several experiments are carried out to evaluate the security of the newly introduced algorithms: entropy, key space analysis, statistical and differential attacks. The results obtained show clearly that the proposed algorithms are secure enough to resist any type of known attacks. A comparative study with a similar algorithm operating in the Discrete Transform Domain (DCT) and the state-of-the-art methods validates the superiority of moments’ domains particularly in highly textured images.