Robust Hybrid Plaintext-Related Image Encryption using Hyper Chaos Signal Processing

This paper proposes a novel encryption scheme for digital images, which utilizes chaotic diffusion in spatial-domain and plaintext-related shuffling in frequency-domain based on a hyper chaos, where the initial values of the hyper chaos are served as keys to the encryption. In spatial-domain, the original digital image is diffused using chaotic XOR operation. After that, both phase and magnitude spectra of the cipher image are further encrypted using chaotic shuffling. The highest entropy and lowest correlation are achieved for the sample image in the proposed hybrid plaintext-related encryption, in which a huge key space of 6.5x1064 is created due to the multi-fold encryption algorithm. The high-level security of the proposed hybrid encryption is also verified with the capability against various attacks. In addition, the hybrid encryption scheme is optimized via the performance comparisons among the encryption procedures.