| At present,the application of the Internet in China is becoming more diversified.People's daily activities are highly dependent on the Internet.We use the network to transmit various kinds of data to realize the interaction of information.Among them,images are vivid,intuitive,and are widely used.However,when images are transmitted,they are vulnerable to attack and damage by network hackers.Security incidents such as information leakage occur frequently.Once some confidential pictures,such as military and commercial pictures are stolen,the consequences are very serious.Therefore,it is necessary to design and use image encryption technology to protect the image transmission and storage security.The unpredictability and internal randomness of chaotic systems provide advantages for digital image encryption.The conventional encryption scheme encrypts all the pixels of the image,and the resulting ciphertext image is the same size as the original image.In addition,when the image size is large,it is necessary to compress and encrypt the image to reduce the amount of data transmitted and stored.Compressing and encrypting the image with compressed sensing,which can compress and encrypt at the same time in the process of sampling,has been widely concerned by people.Based on this,two kinds of image encryption algorithms are proposed in this paper,specifically:(1)A color image encryption algorithm based on Latin square scrambling is proposed.Firstly,the color plaintext image is divided into three components of R,G,and B.For each component,a block scrambling based on a Latin square and chaotic sequence(BSLSCS)is randomly used to scramble the pixels of each block to different rows and columns.Then,the diffusion operation that dependent on the plaintext and scrambled image(DODPSI)is used to change each component pixel value to obtain a ciphertext image.Among them,preprocessing is performed before G and B components are diffused,that is,we xor the last pixel of the R component and the first pixel of the G component,and xor the last pixel of the G component and the first pixel of the B component.Then the diffusion can be transferred from one component to another component.It can improve the security of the algorithm.In addition,this paper proposes a chaotic sequence selection mechanism based on plaintext and digital permutation(CSSMPDP),which dynamically generates scrambling and diffusion sequences for use in the scrambling and diffusion of R,G,and B components.The plaintext is closely related and increases the anti-attack ability of the algorithm.Finally,the effectiveness of the algorithm is verified by experimental simulation and security analysis.(2)An encryption algorithm based on memristive chaotic system and compressed sensing is proposed.In this paper,a new type of magnetic-controlled memristive chaotic system is used,combined with elementary cellular automata,to design a compression encryption algorithm,which can encrypt images while reducing the amount of data transmitted.First,the original image is subjected to a discrete wavelet transform to obtain a sparse coefficient matrix.Then,after scrambling the sparse coefficient matrix with the zigzag scrambling method,the elementary cellular automata scrambling is used.Next,using the measurement matrix generated by the memristive chaotic system to compress and perceive the scrambling image,the final ciphertext image is obtained.Finally,the effectiveness of the algorithm is verified by experimental simulation and security analysis. |
