Optimization Design Of Chaotic S-box With Its Application In Image Encryption

Grow with each passing day,the rapid development of computer network makes the demand of mass information dissemination and private information security increase day by day,and also promotes the research process of modern cryptography.With the development of research,more and more attention has been paid to chaotic system by information security researchers.Chaotic system has many properties that are consistent with cryptography,such as initial value sensitivity and pseudorandomness,which makes the combination of the two become a reality.Cryptography has entered a new research field.This paper focuses on the design and application of S-box based on chaotic system.Using the characteristics of chaotic system as optimization algorithm to screen S-boxes and combining with swarm intelligence optimization algorithm to construct chaotic S-boxes,the designed chaotic S-boxes are applied to image encryption algorithm:(1)A new construction method of S-box optimized by chaotic map is proposed in this paper.Two different pseudo-random numbers are generated by chaotic iteration,and the corresponding position serial numbers of the two pseudo-random numbers in the S-box are found.The elements above,below,left and right are selected for one-to-one transposition,and the elements of the S-box are rearranged,so as to change the sorting structure of the S-box.The differential uniformity,nonlinearity and independence of output bits of the S-box are taken as the weighting formula to measure the performance of the S-box,In order to judge the cryptographic performance of the two S-boxes before and after transposition,the S-box with better performance is selected to replace the current S-box.Cycle the above steps until the optimal S-box is output.The experimental results show that an S-box with better cryptographic performance can be obtained by fast iterative optimization based on chaotic map optimization.(2)An S-box design method based on discrete chaotic map and improved artificial bee colony algorithm is proposed in this paper.First,the S-box generated by chaotic sequence is initialized by reverse learning.The dual transposition function is used to make full use of the advantages of group intelligence algorithm to learn from each other,to keep its own advantages and to learn the advantages of the population,to realize mutual learning and self-learning among the populations,so as to achieve better quality of the population.In addition,the nonlinearity and differential uniformity of S-box are regarded as the evaluation criteria for searching S-box,and the performance comparison condition before and after the S-box is updated.The experimental results show that the cipher performance is better than that of the Sbox based on the mixed mapping optimization by improving the optimization of the S-box.(3)Image encryption method is proposed based on chaos cascade and chaos S-box permutation.Firstly,the plaintext image is initially scrambled by L-T cascaded chaotic map,and then the scrambled image is divided into blocks,then it is replaced with the chaotic S-box designed in Chapter 4.Thereafter the encrypted image is obtained by further diffusion of the sub blocks by L-L cascaded chaotic map.Finally,the encryption effect is analyzed and tested in detail.The experimental results show that the performance of the algorithm is close to the reference value and has good encryption performance.