Research On Chaotic Image Encryption Algorithm Based On Scrambling Diffusion Mechanism

As computer networks and information technology are developing rapidly,and the ratio of transmission using images as carriers is gradually increasing.Since images carry a lot of information,which may involve personal privacy,it is necessary to provide security for images.A large number of scholars have found that in the process of chaos and cryptography research,cryptosystems based on chaos have excellent performance.This paper studies the image encryption algorithm based on chaos theory.In order to obtain a safe and effective encryption scheme,it is necessary to select a suitable chaotic system as the key sequence generator,and effectively combine the scrambling algorithm and the diffusion algorithm to construct a reasonable image algorithm framework.To this end,this article does the following:The basic concepts of chaos theory and cryptography are expounded,the dynamic characteristics of classic chaotic systems are analyzed and a three-dimensional continuous chaotic system is constructed.The correlation between chaos theory and cryptography is discussed,which shows the feasibility of applying chaos theory to cryptography and lays a theoretical foundation for further research.In order to obtain excellent pseudo-random sequences,the discretization and quantization of continuous systems are studied in this paper.The quantitative methods used commonly have been studied and improved,and the results show that the improved quantization method can effectively avoid the existence of a large number of long-run sequences,of which the improved Lorenz quantization method has the best performance.Using NIST test,it is verified that the sequence generated by the above method can be used for image encryption.In this paper,the commonly used spatial domain scrambling and diffusion algorithms are studied,and the encryption effect is analyzed.By deducing the Josephus traversal process,an improved Josephus image scrambling algorithm is proposed.The algorithm can reduce the correlation between adjacent pixels more effectively and providing a basis for the design of encryption algorithm structure.Combining chaos theory,improved Josephus scrambling algorithm and diffusion algorithm,a chaotic image encryption algorithm based on scrambling and diffusion mechanism is proposed.This algorithm has higher security than traditional encryption algorithms and can effectively resist the selection of plaintext and known plaintext attacks.Through building GUI interface,it can meet the user’s needs for the encrypting selected area,so that the study has a certain value.