Research On Generalized Synchronization And Chaos Masking Secure Communicatio

Due to the rapid breakthrough of communication technology in terms of transmission distance and bandwidth,some confidential private information needs to be transmitted through public channels.With the continuous development and application of various information technologies,the security of communication has become an essential issue.The inherent randomness and unpredictability of chaotic systems have allowed for extensive research into the idea of controlling the characteristics and states of chaotic phenomena and applying them to secure communication.With the gradual development of chaotic synchronization theory,the secure communication system based on complete synchronization have been researched.Aiming at the issues of security performance and lack of randomness in the transmission process of the fully synchronous secure communication system,this thesis designs a generalized synchronization algorithm based on the generalized chaotic synchronization theory to improve the security performance.Aiming at the flaws of the security performance of the classic single-level chaotic masking method,this thesis proposes a dynamic multi-level chaotic masking method to improve the security performance of the single-level masking encryption algorithm.The main research contents of this thesis are as follows:(1)Several generalized synchronization methods,including anti-synchronization,projection synchronization and delay synchronization,are researched and summarized.An adaptive generalized rotation synchronization method is designed according to the security design requirements of generalized mapping,and a fixed-axis rotation synchronization method is designed based on the idea of generalized function projection synchronization method,and unknown parameters are identified through adaptive synchronization.Theoretical analysis of Lyapunov function stability of the synchronization method is carried out to prove its effectiveness.Then,on the basis of the above methods,by introducing time variables into the synchronous controller,an improved time-varying axis adaptive generalized rotation synchronization method is further proposed,and it is also proved and simulated.(2)Aiming at the relatively limited secrecy of the single-level chaotic masking method and the little improvement in encryption security compared with the traditional spread spectrum encryption method,a dynamic multi-level chaotic masking method is constructed to improve the security of the secure communication system.The method of dynamic sampling selection and multi-level masking with the highest four-level masking channel increases the security of encrypted information in the security system.Through simulation analysis,the decryption situation of the method under the conditions of correct decryption,wrong decryption,simulated channel noise and dynamically selected channel is researched.(3)The modular design of the FPGA platform is briefly explained,and then the modular design is carried out for the principle of the generalized chaotic synchronization and chaotic masking encryption method,including the chaotic discretization sequence generator module,the chaotic sequence generalized synchronization module,the multilevel chaotic masking module design.Aiming at the condition of limited precision of the FPGA platform,the classical Euler discretization method is used to construct the chaotic discretization sequence generation module of the unified chaotic system.The discretized chaotic sequence is then tested for autocorrelation.In the chaotic sequence generalized synchronization module design,the response system is discretized and the synchronous controller is designed according to the Lyapunov function stability theory,so that the system dynamic error system tends to be stable,and then the generalized chaotic synchronization is established according to the generalized mapping matrix.Simulation results show that the above modules can run successfully.