Research On Dynamic Characteristics Of Composite Chaos System And Its Application In Secure Communication

The types of classical one-dimensional chaos mappings are limited,and most of them are simple in form,single in parameters and uneven in time series distribution,which greatly limits its application in network communication and information security.Because of the diversity of types and structures,the new system composed of multiple one-dimensional chaos mappings can provide more space for the research and application of chaos theory.Therefore,how to grasp the characteristics of composite systems systematically and comprehensively has become a key and research highlights in nonlinear dynamics research and application.Firstly,the initial error is taken as the research object,and the initial error divergence characteristics of the composite system are accurately analyzed by quantitative analysis of its transfer process in the repeated iterations of the system.The theoretical derivation and experimental results show that the analytical results provide a universal basis for accurately evaluating the chaos characteristics of the composite system.Secondly,the paper takes one-dimensional Logistic mapping as an example to show that the construction of multi-level cascades of the system results in the exponential growth of the number of fixed points in the system,transformation of the stable state of the fixed points in the iterative process more complicated.This kind of system dynamic behavior not only provides a large space for expanding the number of secret keys,but also makes the time series generated by system have higher sequence complexity.Thirdly,based on the maximum entropy theory,the paper constructs a one-dimensional Logistic mapping multi-level cascade homogenized system model on the premise of maintaining the integrity of the dynamic structure of the system.entropy analysis shows that compared with several recently proposed one-dimensional coupled mappings,this mapping has better pseudo-random properties based on inherited chaos characteristics.Finally,an image encryption algorithm is constructed,taking the multi-level logistic cascade homogenized mapping as the core of the pseudo-random number generator,for a three-step process structure of bidirectional encoding,location disturbance,and gray-scale masking.The analysis of histogram of cipher-text pixels,correlation of neighboring pixels,information entropy and anti-differential attack test shows that the algorithm has better encryption effect and higher security than the existing encryption algorithm.