Nonlinear multiple-image encryption based on mixture retrieval algorithm in Fresnel domain

We propose a novel nonlinear multiple-image encryption based on mixture retrieval algorithm and phase mask multiplexing in Fresnel domain. The encryption process is realized by applying the Yang-Gu algorithm cascaded with a modified Gerchberg-Saxton algorithm (MGSA), which generate a private key and an intermediate phase to ensure high security. In the proposed method, all images are encoded separately into a phase only function (POF). Obtained POFs are integrated into a final POF based on phase mask multiplexing. As a result, cross-talk noise is removed resulting in a large improvement of the encryption capacity. A spatial light modulator (SLM) based optical setup has been suggested for decryption. Numerical simulations are presented to demonstrate the feasibility and effectiveness of the proposed system. Results also indicate the high robustness of the system against occlusion and noise attacks.