Asymmetric multi-image wavelength multiplexing cryptosystem using QZ algorithm and unequal modulus decomposition

Abstract

An asymmetric multi-image cryptosystem based on wavelength multiplexing is proposed in this paper. Multi-image characteristic of the encryption process has been realized by the QZ synthesis process. Unequal modulus decomposition is used to make the scheme robust to any basic cryptographic attacks. The encryption process has a complex setup that involves phase retrieval algorithms but the decryption is quite simple and fast and can be realized on the hybrid system. Although the scheme is validated on grayscale multi-images, it can also process color images. Cryptosystem is exposed to statistical attacks, noise attacks, and data loss attacks, apart from basic cryptographic attacks. Simulation established the fortitude of the cryptosystem to these attacks. We also analyzed the key space and key sensitivity, and the results show that the cryptosystem has a large key space to resist any brute-force attack. Comparative analysis with similar schemes on multi-image reveals that the cryptosystem has several merits and it is secure against basic and special attacks.