Research On Image Encryption Algorithm Based On Chaotic System And Block Scrambling Diffusion

The rapid development of the Internet has led to an exponential increase in the speed of information dissemination in the network.More than 3 billion images are transmitted on the network every day.Once the private information in the image is obtained by illegal users,it will directly harm the interests of image owners.Therefore,it is particularly important to ensure the secure transmission of images in the network.Image encryption technology transforms the plain image into a noise-like image,which can effectively hide the information in the plain image and solve the security problems encountered in the process of image transmission.In recent years,image encryption technology has become the focus of current research,and various encryption algorithms have been proposed.These algorithms have their own advantages,but some algorithms cannot effectively balance the security and efficiency of the algorithm.Therefore,based on the existing research,this paper proposes an image encryption algorithm based on chaotic system and block scrambling-diffusion.The main research contents of the algorithm include the following two aspects:(1)An image encryption algorithm based on HMI map and square matrix coding is proposed.The algorithm solves the problem of unbalanced performance and algorithm efficiency of chaotic systems.Firstly,the Henon-Modulated-Iterative(HMI)map is constructed by coupling,and the chaotic characteristics of HMI map are analyzed by bifurcation diagram,Lyapunov index and balance degree.Then,the plaintext image is converted into a hexadecimal matrix.At this time,the pixel value of the plaintext image is composed of two letters,and the position of the two letters is exchanged to change the image pixel value.Finally,a random sequence generation module is designed by using a convolutional neural network.The coordinate matrix is scrambled by the generated random sequence.After the scrambled image is divided into blocks,the square matrix coding and hexadecimal non-sequence diffusion are performed to make the pixel values evenly distributed.The experimental results show that the algorithm has a large key space,and each test index is close to the ideal value.It has the ability to resist various attacks and can effectively realize single image encryption.(2)A multi-image encryption algorithm based on cascaded modulation chaotic system and block scrambling-diffusion is proposed.The algorithm solves the problem of insufficient security after a single chaotic map is used for image encryption.Firstly,a cascade modulation chaotic system(CMCS)that can generate multiple complex chaotic maps is constructed,and the advantages of CMCS are fully utilized to achieve one-time pad encryption.Then,the SHA-512 operation is used to generate the key value related to the plaintext,and the three images are fully confused by the block operation and the double scrambling mechanism.Finally,the scrambled image is converted into a bit-level matrix and divided into blocks again.The bit-group diffusion and non-sequence diffusion mechanisms are used to change the statistical characteristics of the image and improve the security of the algorithm.The experimental results show that the algorithm has a large key space,H(S)= 7.9998,NPCR = 99.6289,UACI = 33.5006,and can resist various attacks.The algorithm can encrypt multiple images at the same time,which further improves the efficiency of the algorithm.Figure [26] Table [14] Reference [79]...