Study On Spatiotemporal Chaos Based Image Encryption Algorithm

Because of the advanced coding technology and network,a large number of media files are shared and stored online,which causes a growing problem that using media files,for example,images,illegally on the Internet.Therefore,it is of great value and significance to study the image encryption systems to ensure the confidentiality of digital images and prevent unauthorized access.With futher study,the chaotic cryptography comes into being and has a good development;then the spatiotemporal chaos system has a great used on digital image cryptography systems' construction,because of its high complexity and extensive existence.In this dissertation,two kinds of digital image encryption algorithms based on sptiotemporal chaos system are proposed and summarized as follows:A novel bit-level image cryptosystem is proposed by introducing a new coupled map lattices(CML).The modified non-adjacent spatiotemporal chaotic system with good dynamic performance is constructed by coupling the piecewise-linear chaotic map(PWLCM)in a non-adjacent manner.In the proposed bit-level image cryptosystem,the binary plain image is scrambled globally by a 2D hyper-chaos system.And the confused image is then diffused via the pseudo-random sequences produced quickly and efficiently from the fabricative CML.Computer simulations and performance comparisons with recent image encryption algorithms demonstrate the superior performance and high security of our proposed cryptosystem.An adaptive color image encryption algorithm is proposed by combining spatiotemporal chaos with high-order cellular neural network(HCNN).In the scheme,the pixel scrambling follows the Inter-layer control.Besides,a single-layer sensor network model is intoduced to establish diffusion system,the spatiotemporal chaos and HCNN system are regarded as the chaos sequence generator,the anti-plaintext attack capabilities of the scheme is improved benefit by the CBC diffusion pattern.