Image Encryption Based On Chaotic System And DNA Computing

With the rapid development and application of technologies such as artificial intelligence,Internet of Things and big data,cyberspace security is facing great challenges and threats at the same time.The security issues during transmission and storage of digital information has become a hot topic.Image information is the mainstream information carrier,and the research of image encryption security becomes more and more important.Therefore,finding a scheme that can enhance the security of encryption image is very meaningful.In this dissertation,two image encryption algorithms combining the chaotic systems with DNA computing are proposed,and the security of two proposed encryption algorithms are analyzed.The main works are as follows:(1)A Double-image encryption algorithm based on spatiotemporal chaos and DNA deletion and insertion operations is designed.A pseudo-random key stream of controlling the node and the length of DNA computing is gained by a spatiotemporal chaotic system of non-adjacent coupling.To scramble the two encryption images,the DNA deletion and insertion operations are used in each row and column of the two encrypted images.Then,the two scrambled DNA images are served as keys to encrypt each other,the keys are cross-diffused with each row and column of the same DNA operations,and the two encrypted images are obtained.The simulations and performance analyses have proved that the image encryption scheme can resist exhaustive attacks,statistical attacks and differential attacks,and has good robustness.(2)By combining hyper-chaotic system with the DNA connection operation,an image encryption algorithm of two-way diffusion is designed.To improve the security of the cryptosystem,a hash function is introduced to generate a 512-bit hash value to update the initial values and control parameters of the hyper-chaotic system,so the chaotic sequence has better randomness.The structure of "forward diffusionScrambling-Backward Diffusion" at the DNA level is adopted in encryption algorithm,and the DNA calculation is fully applied to image encryption.The structure of encryption algorithm not only can innovate the DNA computing,but also improve the security of encryption algorithm.DNA connection operation is a kind of operation similar to DNA XOR.There are 16 effective connection methods.The DNA matrix is forwardly diffused by DNA connection calculation,and the positions are exchanged one by one.Finally,the DNA connection operation is used for backward diffusion.The encryption image is obtained after decoding the diffused DNA matrix.Simulation experiments verify the feasibility and high security of the encryption scheme.