A Research Of Image Encryption Algorithm Based On Time-varying Discrete Spatiotemporal Systems

With the development of computer network technology, The security problem of digital image has become a focus problem widely concerned, It is one of the network information security and confidentiality of communications technology problems to be solved that how to effectively ensure the security of the network image transmission.Currently, the main technical secure transmission of information is using cryptographic algorithms to encrypt the information transformation, and it needs for information to seemingly haphazard classly random transformation to encryption transform.Currently, the use of chaotic randomness to construct cryptographic algorithm is one of the hot image encryption algorithm has important theoretical and practical significance.This paper studies the use of discrete chaotic sequence cipher system design problems. First, in theorety rigorously proofing the chaos of a new two-dimensional discrete space-time-varying system, and analyzes the class of random nature of such a chaotic sequence generated by the system using the simulation method; then,designing a new stream cipher algorithm combining the two-dimensional system and Logistic chaotic system, as a digital image encryption algorithm; finally, it verifies the effect of the digital image encryption algorithm with simulation method..The main section of the work done by the paper are as follows:First, the paper proposes a new two-dimensional time-varying discrete space-time systems, and uses the mathematical methods to prove that the system is strictly Devaney chaos, it proves that the system is transitive,dense periodic points and sensitive dependence on initial value sex. The new chaotic system has constructed a theoretical innovation, and lay the foundation for key stream generator behind thedesign of stream ciphers;Second,it analyzies the varying discrete spatiotemporal chaos of multiple pseudo-random nature of the sequence.MATLAB simulation is done from chaos, the relevant inspection and initial sensitivity of these aspects. The simulation results show that chaotic sequences meet the requirements of the characteristics of the pseudo-random list.This provides protection for the entire encryption algorithm results.Finally, combining with two-dimensional logistic system and time-varying discrete chaotic systems, it proposes a new image encryption algorithm and the algorithm using Matlab language proposed in this paper carried out simulation experiments, and from the key sensitivity, anti-statistical attack, several anti-noise attack conducted a safety analysis.The analysis results show: the security of the algorithm is, to some extent,Especially the anti noise attack and anti attack ability and sensitivity of Statistics.