Abstract: To solve the problems of simple structure,low security and strong correlation of single chaotic system,a ch-aotic system image encryption algorithm based on dynamic parameter control was proposed.Firstly,a new chaotic system (LCT) is constructed to generate chaotic sequences,which are sorted to get a set of sequences,and the original positions are indexed to get a set of position index sequences,and image moments are obtained.The array is scrambled according to the sequence of index positions obtained.Secondly,a new method of generating pseudo-random sequence is designed by using two chaotic sequences obtained from Henon chaotic map,and a new chaotic sequence is obtained.The new ch-aotic sequence and the scrambled image are XOR processed to obtain the final ciphertext image.Experiment results show that correlation between ciphertext image and plaintext image is small,and the test values of NPCR and UACI are 99.6414%,99.6380% and 33.3869%,33.3852%,respectively for two pixel values of plaintext image,which are close to the theoretical value;the entropy value of plaintext image is 7.4416,and that of ciphertext image is 7.9889.Therefore,the algorithm has strong robustness,reliable security,and can effectively improve the anti-attack ability of encryption system.

Key words: Henon chaotic system, Image encryption, Index sequence, LCT chaotic system