Hyperchaotic Synchronization And Its Application Of Secure Communication

Chaos is a quasi-stochastic phenomenon appearing possibly in definite nonlinear dynamic systems. Chotic motion is a complex nonlinear motion and the chaotic phenomenon has been observed in a lot of real systems. The dynamic properties of chaos signal such as ergodicity, aperiodic, uncorrelated, broadband and noise-like have been proved to be useful for secure communication. The chaotic synchronization is the theory basis of secure communication. The research of the chaotic synchronization and its application becomes a new research focus in nonlinear science fields.The main content of this paper contains the analysis of hyperchaotic synchronization and application of hyperchaotic secure communication. In this dissertation, the main contributions are as follows:1. According to the actuality and development tide of domestic and foreign research, systematic review is presented about, chaotic synchronization and its application. And the important methods of synchronization that have practical and theoretic value, drive-response synchronization, state feedback synchronization and synchronization based on state observer. Based on these researches, the improved approach about nonlinear feedback synchronization is proposed, chaotic synchronization is achieved using this approach with less feedback.2. In this paper, the observer-based hyperchaotic synchronization, the hyperchaotic generalized synchronization and the time-delay hyperchaotic synchronization are researched thoroughly. The synchronous performance is analyzed with noise interference and uncertain parameters. And the improved approach about time-delay hyperchaotic synchronization basedon coupled method is proposed, and the robustness is proved.3. Four main messages encoding schemes based on chaotic synchronization were developed: chaotic masking, chaos modulation, chaos shift keying and chaotic spread spectrum. The possibilities for the solution of the problem about hyperchaotic communication are explored. The feasibility of the communication scheme in the hyperchaotic system is demonstrated through simulation. The hyperchaotic communication scheme based on observer and improved secure communication scheme about time-delay hyperchaotic system are designed. Better fidelity and the security are showed through simulation.4. A multistage time-delay hyperchaotic system for secure communication is researched. The schemes can resist attacts of reconstructing attractor.