A Multi-Image Encryption with Super-Lager-Capacity Based on Spherical Diffraction and Filtering Diffusion

Abstract

A multi-image encryption with super-large-capacity is proposed by using spherical diffraction and filtering diffusion. In the proposed method, initial images are processed sequentially by filtering diffusion and chaos scrambling. The images are combined into one image using XOR operation. The combined image is encrypted by improved equal modulus decomposition after spherical diffraction. There are three main contributions of the proposed method—(1) resisting phase-retrieval attack due to the asymmetry of spherical diffraction; (2) high flexibility of decrypting images individually; and (3) super-large encryption capacity of the product of image resolution and grayscale level, which is the most significant advantage. The feasibility and effectiveness of the proposed encryption are verified by numerical simulation results.