Multiple Color Image Encryption System Based on Hybrid Digital/Optical Techniques and Assisted by 18D Memristive Chaos

An eighteenth-dimensional (18D) memristive chaotic generator characterized by grid multi-double-scroll (GMDS) attractors is proposed.The chaos has the highest chaos dimension reported in the literature for image encryption purposes.The chaotic sequences are used to assist the operation of proposed hybrid digital/optical encryption and decryption systems for multiple color images.The encryption system consists of a digital encryption subsystem (DEsS) cascaded with an optical encryption subsystem (OEsS) which are controlled by six and twelve chaotic sequences, respectively.The DEsS is implemented using four sequential stages (compressive sensing, scrambling, DNA encoding, and diffusion).The OEsS works parallelly on the RGB components of the digital encrypted image and implemented using double-chaotic phase encoding in Fourier, fractional Fourier, and gyrator optical transforms domains, respectively.All the used methods work interactively to increase the security level and robustness of the proposed encryption system.The simulation results show that the proposed encryption system works very satisfactory even with a 64-image input (plain) template.The entropy factor reaches 7.9997 and 7.9998 for encrypted single and multiple color images, respectively.The key space of the proposed system is 2 2551 which is the highest among other image encryption systems reported in the literature.The simulation is performed using MATLAB Ver.2022a and applied to images taken from Linnaeus 5 dataset.