Design Of Cascaded Hyperchaotic System And Its Application In Image Encryption

In the background of the speedy advances of the big data era,a large amount of text,image,audio and other information is constantly transmitted and stored in the network.Therefore,the protection and security of this information are receiving more and more attention.Compared with words,images are more intuitive and vivid,and can convey richer and more complex information.Compared with traditional encryption technology,chaotic encryption technology has more advantages in image encryption because chaotic system has the characteristics of initial value sensitivity and high complexity.However,most researches on chaotic encryption schemes tend to pay more attention to the security of image encryption and ignore the application value of the schemes in practical applications.Based on this,this paper proposes a more suitable chaotic image encryption scheme.Firstly,for improve the traditional low dimensional mapping with few parameters,small parameter space and low complexity,a high dimensional discrete hyperchaotic system(Sin-Tent-Sint system,S-T-S)is proposed by combining two cascade methods.The performance analysis shows that S-T-S system has extremely high complexity,wider parameter range and can generate hyperchaotic dynamic behavior,which is suitable for the pseudo random number generator used in image encryption.Then,Secondly,a compressed sensing dual color image encryption scheme based on S-T-S system and Rubik’s cube scrambling is proposed.Considering the burden of storage and transmission brought by excessive ciphertext information,in order to reduce the size of ciphertext images,measurement matrix is constructed based on the sequence generated by S-T-S system,and the image is compressed and encrypted at the same time by combining two-dimensional compressed sensing technology.Then,a Rubik’s cube scrambling algorithm based on chaotic sequence is designed,which combines the layers of two images into a cube that can be expanded in different orders,and swaps the pixels of the rows,columns or faces of each image by rotating the cube to achieve image scramble.This algorithm can break the correlation not only of neighboring pixels within an image layer but also of pixels between different layers of the image.Finally,the image is further diffused using the hyperchaotic sequence.The algorithm can achieve both compression and encryption of dual color images.Experimental results show that the proposed compression encryption scheme has good compression recovery performance and the ability to destroy the correlation between different layers of the image,and can well resist statistical attacks and has high security.