Stream Cipher Algorithm Based On Complex Chaotic System

Due to data breaches,security issues have been common in recent years,information security is not only closely related to individuals,but has risen to the height of national security strategy and has received unprecedented attention.The introduction of some nontraditional methods into the field of information security has become a hotspot of academic research.Streaming cryptography system is widely used in wireless communication,so the use of pseudo-random,unpredictable chaotic system for the design of flow cipher algorithm has been paid attention to by researchers.In the common complex chaotic system,the spatiotemporal chaos has been widely used because of its chaotic behavior characteristics in time and space,and its typical example is the coupled image lattice(CML)model,which has more positive Lyapunov exponent,and the system is chaotic in time and space direction.Its dynamic behavior is very complex,so it is very suitable for designing stream cipher algorithms.However,in the application of two-dimensional CML model,researchers often apply it directly to the design of stream cipher algorithm,and they don't systematically analyze the cryptographic feature of the chaotic system itself,which makes it lack sufficient theoretical support for the application of chaotic secure communication.Therefore,this paper has carried on the relevant research to these need to continue the in-depth research point,at the same time,it is found that the probability density of the system is not uniform in the process of detecting the change of its probability density with the parameters.So from the point of view of cryptography,the characteristics of the coupling map lattice model are analyzed and its application in the stream cipher is studied.The main research work in this paper is as follows:1.The cryptographic feature of two-dimensional coupled map lattice(2D CML)with piecewise logistic map is analyzed,and the analytic expression of its Lyapunov exponent spectrum is given.The results of this model provide theory basis of the application of process parameter settings.2.Aiming at the problem of uneven probability density of PLM-based CML model,a solution was proposed to achieve approximate homogenization of probability density by adding different offset for each lattice.And the improved model was analyzed,the analysis results show that the improved model has better cryptography feature than other model.3.Using the improved model as the core component,a stream cipher algorithm with efficiency and security is constructed by combining the common nonlinear functions and partition cellular automata.4.Using NIST test suit,the stochastic test of the algorithm is been tested.The proposed algorithm in this paper is analyzed and tested from the aspects of the security,relevance,efficiency.These analysis results show that the proposed algorithm is safe and effective.