Image Encryption Schemes Based On Chaos And DNA Encoding

With the rapid development of computer technology,the use of Internet is becoming more frequent.As a kind of information carrier,image has a vivid and intuitive effect,and plays an increasingly important role in network communication.Therefore,it is very important to ensure its security.Because of the large amount of data and high redundancy,the traditional encryption algorithm is no longer suitable for image encryption.The pseudo-randomness and sensitivity to initial values of chaotic systems are very suitable for image encryption,so chaotic image encryption has become a research hotspot.This paper mainly studies the combination of chaotic system and DNA coding to improve the parallelism of the algorithm operation,and combines the encryption algorithm with the plaintext information to achieve one-time pad effect.The main tasks as follows:(1)An image encryption algorithm based on adjacent coupled map lattice(CML)and DNA coding sequences is proposed.First,an encoding rule is randomly selected to encode the original image into a DNA matrix,and then the odd rows and columns of the DNA matrix are cyclically transformed,and then the even rows in the scrambled DNA matrix are further indexed and scrambled.The DNA matrix after scrambling is subjected to a diffusion operation using the DNA sequence generated by the CML system and the designed DNA calculation rule.Finally,the DNA matrix after the diffusion is subjected to a DNA decoding operation to obtain a final encrypted image.(2)An image encryption algorithm based on pseudo random bit sequence and DNA plane is proposed.The pseudo-random bit sequence generation system(PBSG)is designed using a coupled map lattice,and the system is used to generate random sequence required in the encryption process.The plane image is decomposed into four DNA planes,and then the four DNA planes are subjected to row cyclic permutation and column cyclic permutation.Diffusion operations were then performed on the four DNA planes in conjunction with DNA calculations.Finally,the four DNA planes are decoded and combined into a matrix of pixels,then the final cipher image can be obtained.Throughout the encryption process,the choice of DNA encoding and decoding rules is determined by the PBSG system,which greatly enhances the randomness of the encryption process and makes the encryption better.(3)An image encryption algorithm based on cat map and DNA plane is proposed.The algorithm uses a customized global coupled map lattice to generate the chaotic sequences needed for the encryption process.The plane image is encoded into four DNA planes according to randomly selected DNA coding rules,and then the four planes are performed to DNA level scrambling and diffusion.DNA scrambling uses the cat mapping ingeniously,while the DNA-level diffusion operation designs DNA calculation rules suitable for the algorithm based on the three operations of the DNA sequence.All three encryption algorithms are highly correlated with plaintext information,and the diversity of DNA coding and DNA sequence operations is utilized as much as possible,and the parallelism of the encryption program can be realized to a certain extent,taking into consideration the safety and efficiency.The author used Matlab as the experimental platform,and carried out simulation experiments and related security analysis on the algorithm.