Image encryption based on a fractional-order hyperchaotic system and fast row-column-level joint permutation and diffusion.

Integer-order hyperchaotic image encryption has demonstrated significant potential in ensuring image security. Recent research suggests fractional-order hyperchaotic systems typically exhibit superior chaotic characteristics to integer-order ones. As a critical operation in image encryption, diffusion usually changes the values of the image pixel by pixel, resulting in low efficiency. At the same time, most image encryption approaches conduct the diffusion and the other operation, permutation that changes the positions of pixels, separately, leading to a high risk of being cracked. To address these issues, an image encryption approach based on a newly designed fractional-order hyperchaotic system and fast row-column-level joint permutation and diffusion, termed FHFJPD, is proposed in this paper. A new 5D fractional-order hyperchaotic system is designed to generate pseudorandom sequences, and the corresponding analysis demonstrates its favorable complex dynamical characteristics. With the sequences generated by the designed fractional-order hyperchaotic system, we propose a novel joint permutation and diffusion scheme that can change the pixel values row by row or column by column rather than point by point as in typical image encryption schemes. Various experimental results demonstrate that the proposed FHFJPD exhibits excellent security and performance for image encryption. [ABSTRACT FROM AUTHOR]