LAUSR

With the development of information technology, security, low latency, and instant messaging have become a major demand. To solve this problem, this paper designs a secure and efficient image cipher algorithm. Firstly, a new four-dimensional hyperchaotic system with strong chaotic performance is proposed. Secondly, a dynamic high-performance S-box generation algorithm is proposed based on GF(28) by improving the method of generating S-boxes in AES, selecting suitable irreducible polynomial as well as affine matrix, precomputing the corresponding affine multiplication matrix as well as multiplication inverse matrix. The S-box algebraic expressions generated by this algorithm have 255 terms and are more resistant to algebraic attacks than AES. Finally, based on the four-dimensional hyperchaotic system and dynamic high-performance S-box generation algorithm, the new image cipher algorithm that can encrypt and decrypt images of arbitrary size is proposed. The image cipher algorithm consists of two rounds of interleaved permutation, two rounds of dynamic S-box substitution and cyclic shift permutation with fixed point. Cyclic shift permutation with fixed point and dynamic S-box substitution ensure that the plaintext transformation can be transferred to the entire image. Through testing, analysis and comparison, the algorithm has proven to be a secure and efficient image cipher algorithm.