Research On Sampled-data Chaotic Synchronization Control Method And Application To Secure Communication

Chaos is one of the most important scientific discoveries and the hottest subjects in the twentieth century’s. From1990s, with the important breakthrough for the control and synchronization of chaos, chaotic synchronization has become an important question for discussion. Because of the scrambling, initial sensitivity and broadband spectrum, chaotic synchronization has been widely used into secure communication system. In this paper, the methods of chaotic synchronization control and how it can be applied to secure communication system are investigated by combining of theoretical analysis, software simulation and circuit design. The main contents are as follows:Firstly, by the scale transformation for Lorenz system, the numerical simulation shows the effectiveness of the transformation and the transformed system remains the characters of chaotic system. And the Lorenz circuit is designed after the circuit simulation by Multisim software.Secondly, in this paper, a feedback synchronization controller with a single variable is designed for the above chaotic circuit. The controller designed can ensure the error system become asymptotic stable by Lyapunov method, and the range of the control gain can be gotten. The numerical simulations and circuit simulations show that the effectiveness of the controller designed. The two chaotic circuits can be synchronized by the controller circuit based on adjusting the amplifier and parameters. The study of chaotic masking secure communication is base on the controller. The circuit implementation of secure communication scheme is very successful by comparing the plaintext, ciphertext and decrypted plaintext.Finally, besides of feedback controller, a sampled-data controller with a single variable is designed for the above chaotic circuits. The theoretical analysis is given to prove the asymptotic stability of the sampled-data error system with the controller designed. The numerical simulation shows the effectiveness of this controller. The chaotic masking secure communication base on the controller is simulated by Simulink. Furthermore, the controller is implemented with C8051F120MCU which ensures the two chaotic circuits to be synchronized.