Research Of Chaotic Synchronization And Its Application In Secure Communication

Chaos is a special moving form of nonlinear dynamics system, and it is definite and random like process. Chaotic signal has the properties of ergodicity, nonperiodicity, continuous broadband power spectra, and noise like etc. Along with the appearance of chaotic synchronization methods, chaotic system synchronization and its application in secure communication have aroused the attention of people. How to find the best scheme of synchronization is becoming today's hotspot and difficulty of research more and more.On the basis of analyzing many kinds of chaotic synchronization methods, three methods of improving the security of chaotic synchronized communication system is studied: choose more complex hyperchaotic system as the chaos generator of modulation; adopt more complex modulating method of information signal; change the transmission method of signal. Theory analysis, computer simulation and numerical computation are combined together and it provides theory and experiment foundations.A new chaotic secure communication scheme based on active-passive synchronization is propoed. By contrast analysis with the original scheme, find that not only the complexity of system is reduced, but also the capability is enhanced. At the same time, it does not destroy the correlation. The experimental results show that the proposed method can recover signals well. The new scheme meets the command of secure communication.According to the principle of synchronization driven by chaotic signal outside, adopt discrete varialbles of Rossler chaotic system to drive two Lorenz systems with equal parameters to achive synchronization. Point out that under some condition, the synchronous effect of the chaotic synchronization scheme driven by intermittent signal has relation with the coefficient of driven intension andsampled period. We applied the chaotic synchronization driven by discrete chaotic signal to secure communication, the system possesses robustness, the information signal can be hiden in chaotic variables, and its keys are resourceful.In the study of hyperchaotic system, the secure communications of hyperchaotic system synchronization without time-delay and with time-delay are discussed. Point out that hyperchaotic system with time-delay has much superiority than that without time-delay. In secure communication, hyperchaotic system is of high security, and it will still be hotpoint in the later time.