Research On Color Image Encryption Based On Five Dimensional Hyperchaotic System

In the information age,the Internet is developing rapidly,and most people are used to transferring information via network.At the same time,information security is also concerned widely.Digital image is one of the important carriers of information.To ensure the security of digital image information,image encryption is one of the most popular methods.In this dissertation,two color image encryption schemes based on five dimensional hyperchaotic system are proposed.A color image encryption scheme based on SHA-256 is designed.The hash value of the plaintext image is calculated SHA-256 function to control the system parameters of Arnold mapping,which enhances the correlation between the parameters and plaintext information.Binary shift and Arnold mapping are used to double scramble the pixel positions of the image.Chebyshev map is used to generate chaotic sequence,while an initial value is given to the hyperchaotic system randomly to generate chaotic diffusion sequence.Finally,the cipher-text image is obtained by diffusion processing.Simulation results demonstrate that the image encryption scheme has strong key sensitivity and large key space,which can better resist exhaustive attack.A color image encryption scheme based on chaotic cellular neural network and zigzag transform is proposed.The initial value of the chaotic cellular neural network system is updated with SHA-256 function,and the image pixels are scrambled by zigzag transform many times to achieve better scrambling effect.The weights of the chaotic cellular neural network system is updated by the composite chaotic map,and the single layer perceptron model structure is introduced into the diffusion process.Simulation results show that the key space of the scheme is larger,and it can resist cropping attack and noise attack.