A novel approach for double image encryption

In this paper, a novel approach for double-image encryption technique is proposed. The chaos function and fractional Fourier transform are employed in this method. The unpredictability and initial sensitivity properties of chaotic system are utilized to generate both the scrambling matrix and the masks for encryption. This method doesn´t need to store all the phase keys which are hidden in the parameters of the chaos. The key space is large enough to make brute-force attacks infeasible. The mean square error between the decrypted and original real image is evaluated; and the robustness with respect to the blind encryption is performed. Simulation results show the validity of the proposed technique.