A New Image Encryption Scheme Using a Hyperchaotic System

Recently, a number of chaos-based image encryption schemes with permutation-diffusion structure have been proposed. In those schemes, the permutation and diffusion are considered as two independent processes, both requiring iteration of a chaotic map/system. In this paper, we suggest a fast image encryption scheme where both processes are driven by a single hyperchaotic system. The permutation table and the diffusion keystream are generated from the same sequence extracted from the orbit of the employed system. The computational efficiency is improved as the total number of iterations is reduced by half. Moreover, the permutation table is created by a sorting mechanism that works on the chaotic sequence, and the strategy effectively avoid the flaw of periodicity that exists in discretized chaotic maps. The security of the proposed scheme is analyzed in detail, and the results demonstrate its satisfactory level of security.