Research On Digital Image Encryption Scheme Based On Novel Discrete Chaotic Maps

With the development of communication technology,people need more and more visual and large information digital image communication.The research of digital image encryption is also becoming more and more important.Chaotic digital image encryption technology is a widely used digital image encryption technology.Its main feature is that due to the initial value sensitivity of chaotic system,the encrypted cipher image realizes randomness and nonrepeatability,which makes it difficult to crack.The digital image cryptosystem based on classical one-dimensional discrete chaotic map is the most prominent,but some cryptosystems are also faced with security threats due to the small key space,independent link between key and plain image and narrow chaotic area.In this paper,from the two aspects of improving the nonlinear dynamic behavior of the classical one-dimensional discrete chaotic map and designing the image encryption scheme,a better performance discrete chaotic mapsystem and a digital image encryption scheme based on the novel discrete chaotic map are proposed.The specific research content of this paper is as follows:Firstly,the classical one-dimensional Sine discrete chaotic map was expanded into threedimensional Sine discrete chaotic map by the way of global remainder after nonlinear coupling.Through the analysis of its dynamic behavior,it was proved that it was hyperchaotic system with three Lyapunov indices greater than zero,it not only expands the chaotic region but also has stronger randomness.In addition,a new sinusoidal cascade discrete chaotic map model is proposed,which uses the sinusoidal cascade of two identical one-dimensional discrete chaotic maps to construct a discrete chaotic map system,which can generate a one-dimensional discrete chaotic mapsystem with a wider parameter range and a wider chaotic region.Secondly,in order to verify the application of three-dimensional Sine discrete chaotic map in digital image encryption,a chaotic digital image encryption scheme based on cyclic shift and horizontal and vertical diffusion was proposed,in which the initial values of three-dimensional Sine discrete chaotic map are updated by plain image information,and the pseudo-random sequence generated by iteration are taken as the passwords.The experimental results and security performance analysis show that the encryption scheme designed has good encryption effect and the three-dimensional Sine discrete chaotic map constructed can be well applied in digital image encryption.Finally,in order to verify the application of the novel sinusoidal cascade discrete chaotic map model in digital image encryption,a chaotic digital image encryption scheme based on spiral traversal and finite field bidirectional diffusion is proposed.The pseudo-random sequence generated by three one-dimensional discrete chaotic maps modified by sinusoidal cascade discrete chaotic map model are used as the password of digital image cryptosystem.The initial values of the system are generated by combining SHA-256,SHA-512,and plain image.Simulation experiment and security performance analysis show that the designed encryption scheme has better performance in execution time and security.