Research On Image Encryption Scheme Based On Coupled And Mixed Spatiotemporal Chaos

With the application and popularization of technology such as big data analysis,cloud computing and mobile internet,the security of cyberspace is facing many threats.The innovation and development of image security technology has already become a hot spot of research.The continuous development of chaotic system theory provides a new direction for image encryption technology.But with the improvement of computing power of software and hardware,some of the original chaotic encryption schemes are no longer safe.Most of the algorithms only use a single chaotic system,or chaotic systems are too simple to ignore the relationship between them.In addition,the structure of some algorithms is also weak,which reduces the security of the system.In this paper,several chaotic image encryption schemes with high security performance are proposed by improving the chaotic system and designing the novel algorithm structure.(1)A color image encryption algorithm,which combines the SHA-3 hash algorithm and two chaotic systems,is proposed.Using the hash algorithm,the image plaintext is connected with the key,and the equivalent one-time encryption effect is obtained.The sensitivity of the SHA-3 algorithm and chaotic systems ensures the effect of a one-time pad.At the same time,the author extends the image to the three-dimensional space and undergoes plane-plane displacements to confuse pixels.The structure of alternating between permutation and diffusion is applied to enhance the level of security.(2)An image encryption scheme based on pseudo-random coupled LP spatiotemporal chaos(PCLML)is proposed.Firstly,author investigated a novel one-dimensional LP modulation map which is derived from the Logistic and PCLML maps and be regard as the basic function of coupled mapping lattices.Secondly,the coupling mode of space is changed which can accelerate the chaotic behavior of the fully spatial chao.Finally,a new image encryption scheme is designed by combining the self generated M matrix and the dynamic S-Box technology.(3)An image encryption scheme based on mixed multi-chaotic coupled mapping lattice(MCML)is proposed.By mixing Logistic,Sine and Tent chaotic systems together,the author solves the simplification of the driving equation,enhances the chaotic characteristics and expands the key space.Meanwhile,a new key generation and distribution scheme is designed to reach the balance between security and time overhead.The nonlinear equation is used to diffuse the pixel value and scramble the image in the form of Z.The double-layer encryption in pixel and bit granularity makes the algorithm more capable to resisting attack.