Research Of Secure Communication Based On Chaos Control Theory

Chaos theory, which is an important branch of nonlinear science, mainly studies the evolution theory on the system changing suddenly from the ordered state to a disordered one and investigates the formation ways and mechanism of the inherent"stochastic process"in the deterministic system. Chaos, the theory of relativity and quantum mechanics are called the third technological revolution in the 20th century. Because of the good properties of chaotic signal such as ergodicity, aperiodicity, continuous broadband spectrum, and noise-like etc., it has great potential application in secure communication. With the rapid development of information technology, information security, chaos theory, the study on chaos synchronization methods and its application in secure communication has both important theoretical significance and widely application prospect. Combining the theoretical analysis with the numerical simulations, the problem of chaos control, chaos synchronization and its application in secure communication is studied in detail.Firstly, chaos control of the R?ssler chaotic system is investigated. By means of the Routh-Hurwitz criterion, the conditions are obtained to suppress chaos of the controlled R?ssler system to unstable equilibrium points. A linear feedback controller is designed to realize chaos control.Secondly, projective synchronization of the fractional-order chaotic systems is studied. Based on the stability theory of the fractional-order linear system and pole placement technique, we construct a state observer for the fractional-order systems to achieve projective synchronization between the drive and response systems. The fractional-order Lüchaotic system is taken as an example to illustrate the proposed method. There is no need to figure out the Lyapunov exponent and it has the ability to realize the projective synchronization at arbitrary scaling factor. The result of the numerical simulation illustrates that the projective synchronization takes less time.Thirdly, by the observer control technique and Routh-Hurwitz criterion, the problem of chaos synchronization for a class of chaotic systems is considered. In the transmitter, we transmit the original information by the chaotic masking method. In the receiver, the information signal can be recovered accurately by applying the proposed synchronization scheme. The result of the numerical simulation illustrates that the strategies this article adopts has a faster synchronization speed and a more accurate decryption.Finally, a secure communications scheme by the parameter modulation method and using Chen hyperchaotic system is introduced. Using adaptive control, we can make the states of two hyperchaotic systems with unknown parameter asymptotically synchronized and identify the uncertain parameter, the information signal can be recovered from the estimated parameter. The communication mechanism by hyperchaotic system is different from low-dimensional chaotic system that the time to extract the information signal and accuracy is not sensitive to the frequency of the information signal. With our method, the information signal can be recovered fast and accurately.