Asymmetric double-image encryption via wavelength multiplexing

Abstract

In this paper, we propose an asymmetric double-image encryption via wavelength multiplexing. First, a novel iterative phase retrieval algorithm, to the best of our knowledge, is developed to encode two images into one complex-valued function via wavelength multiplexing. Then, the function is encoded by equal modulus decomposition (EMD). This cryptosystem not only retains the advantages of EMD but also reduces the number of public keys so as to enhance the resistance to the amplitude-phase retrieval algorithm (APRA). In the decryption, two high-quality decrypted images can be obtained with their corresponding wavelengths. To the best of our knowledge, this is the first time that wavelength multiplexing is used to achieve high-quality two-image encryption and decryption. Numerical simulation results show the effectiveness and robustness of this new method.