Research On Digital Image Encryption Algorithms Based On Chaotic System

In the era of Internet and big data,chaotic-based digital image encryption algorithm research has become one of the research hotspots in the field of information security.Compared with traditional text data,digital image has the characteristics of large amount of data and high redundancy.Traditional encryption methods,such as DES,AES and RSA,have been impossible meeting the requirements of digital image encryption.Because chaos is sensitive to initial values and intrinsic randomness,which coincide with the concepts of confusion and diffusion in cryptography,image encryption technology based on chaos has developed rapidly.This paper mainly focuses on the following research work on chaotic image encryption:An image encryption algorithm based on bit plane and an improved Logistic map is proposed for the dependence of keys on plaintext images.The algorithm takes the low 4-bit matrix of scrambled plaintext image as the control parameter of the improved Logistic map,enhances the dependence of keys on plaintext image,and has a remarkable one-time-one-secret characteristic.The encryption algorithm with different strength is designed to improve the efficiency of the algorithm for the bits with different image information.An image encryption algorithm based on hyper-chaos and block-mod is proposed for the diffusion of image encryption.In this algorithm,chaotic sequences are generated by hyper-chaos system.Around the pixel to be encrypted,an image block of random size is segmented.The gray value of the encrypted pixel is obtained by performing modulo operation on all pixel values in the block.It effectively enlarges the diffusion range and enhances the randomness of diffusion.Aiming at the selection and construction of a chaotic system in image encryption system,a model is proposed for a chaotic system based on the high-order jerk system that features a multiple-direction multi-scroll(MDMS)chaotic attractor.The stability analysis of the system's equilibrium point and Lyapunov exponents,and MATLAB numerical simulations have been performed to investigate the chaotic dynamics characteristics of this system,and a means to effectively determine the system parameters is given.Finally,the chaotic sequence generated by the chaotic system is used to encrypt images.The feasibility and security of the chaotic parameterized model in the field of secure communication are verified.