Security Analysis Of Image Chaos Encryption Algorithm

Chaos Cryptography as an interdisciplinary blend of chaos theory and modern cryptography,has aroused extensive attention of researchers in different fields since the late 1980s.Especially in the era of big data,image chaotic cipher,as a new type of cryptographic technology,shines in the field of privacy protection in network security,and has wide application prospects.However,compared to modern cryptography,chaotic cryptography is a newer discipline,which leads to its lack of theoretical standards to measure the security performance of chaotic cryptographic algorithms.Many chaotic cipher algorithms proposed at the beginning of the study are vulnerable and deciphered,which greatly limits the development of chaotic cryptography.In order to improve the security of the chaotic cryptographic algorithm,this dissertation conducts a cryptanalysis on several image chaotic encryption algorithms,finds the security flaws,and proposes corresponding suggestions for Improvement based on this.The main contents of this article are as follows:1.The security analysis of an image chaos encryption algorithm proposed in 2015 combining image pixel value changes and position permutation was carried out.The algorithm is based on the scrambling-diffusion-scrambling structure,which uses bit scrambling,bit diffusion,and pixel scrambling on the plaintext image to obtain the ciphertext image.The authors make some statistical security analysis and experimental simulations on the ciphertext,and claim that the algorithm has strong anti-attack ability based on the results.After analysis,it is found that bit scrambling encryption is an invalid encryption process for cryptanalysts.The entire encryption process is only related to the key.There is no direct or indirect association wi th the plaintext to be encrypted,and it is vulnerable to differential attacks.Based on this,differential analysis combined with the chosen plaintext attack method was used to successfully crack the algorithm,and several improvements were proposed to the algorithm.Theoretical analysis and experimental results show that the attack methods proposed in this chapter are both low in computational complexity and data complexity.2.A cryptanalysis of an image chaos encryption algorithm based on Bit Cube and Latin Cube proposed in 2019 was performed.The algorithm adopts a scrambling-diffusion-scrambling structure.The main feature is that the chaotic sequence is used to construct the finite field first,and then the Latin cube is generated according to the finite field operation to achieve image encryption.In addition,the algorithm also uses different scrambling rules for the second scrambling based on the statistical characteristics of the ciphertext after diffusion.However,the generation of Latin cubes in this encryption algorithm is not related to the plain text,a nd there is a security vulnerability that makes the algorithm vulnerable to differential analysis during the diffusion phase.According to this analysis result,the chosen plaintext attack was successfully implemented.Theoretical analysis and experimental results show that the time complexity and data complexity of the attack are both low.