Research On Image Block Encryption Algorithm Based On Chaos And ZUC Stream Cipher

With the development of Internet technology and the upgrading of communication equipment,both countries and individuals are facing the threat of network security issues.In daily communication,images that can be seen everywhere have become an important carrier of people's information transmission due to their vivid images and large information carrying capacity.Therefore,image encryption technology has received more and more attention.Scholars have proposed many image encryption algorithms with excellent performance,among which chaos theory is widely used.The pseudo-random sequence iterative from the chaotic system is used to realize the change of the pixel position and pixel value of the image,which is the common scrambling-diffusion operation in the image encryption framework.With the application of chaos theory,one-dimensional chaotic systems with simple structure and fast running speed are found to have problems of insufficient randomness and security.Therefore,this paper combines ZUC stream cipher to improve the shortcomings of one-dimensional chaotic systems,and proposes some block Encrypted image encryption algorithm,in which the advantage of block operation is to improve encryption and transmission efficiency through parallel encryption and decryption processing.The main research contents of this paper are as follows:(1)On the basis of chaotic scrambling-diffusion,ZUC stream cipher is introduced to expand the key space of image encryption algorithm.The one-dimensional chaotic sequence is sampled by the binary sequence generated by the ZUC system,and the Lyapunov Exponent(LE)is calculated to prove that the sampling operation can enhance the randomness of the chaotic sequence.Then,using the sampled chaotic sequence,a random image block method is designed,which reduces the pixel correlation of the plaintext image in the block stage and improves the algorithm's ability to resist malicious attacks.(2)Based on the ZUC sampling of the chaotic system,an image encryption algorithm encrypted in the frequency domain is proposed by using the Reversible Cellular Automata(RCA).After the image is divided into frequency blocks,the ZUC stream cipher is used to control the number of iterations and rules of RCA,and the low-frequency image blocks containing important information are treated differently from other parts,avoiding the same degree of RCA iteration for the entire image,reducing time and resources.waste,and then experimentally prove the security and encryption efficiency of the algorithm.(3)Considering the high redundancy of the image and the limited resources of the communication channel,this paper proposes a block image encryption algorithm based on the chaotic compressed sensing theory.The random block method divides the sparse matrix of the image into blocks.Then use the chaotic sequence sampled by the ZUC system to construct the measurement matrix.Subsequently,the parallel compressed sensing technology is used to realize the compression and encryption of the image,and finally the overall scrambling and diffusion operations are performed.to avoid block effects.The security of the algorithm and the reconstruction effect after compressed sensing are analyzed through simulation experiments.The results show that the introduction of ZUC stream cipher can expand the key space of the algorithm,improve the security,and the sampling operation of chaotic sequences can make the reconstruction effect of the image better.