An Observer-Based Method for Secure Communication

In this paper, Chua´s circuit is adopted to be the chaotic system in both of transmitter and receiver. According to the Pecore-Carroll´s synchronous chaos theory, an n-dimensional chaotic system can be separated as a drive and response subsystem. The drive signal is transmitted to the response system for achieving the system synchronization between the corresponding transmitter and receiver. A dynamic error equation is obtained from the state equations of the driving and responding part, which describe the behaviors of a controller for the chaotic system in the receiver. If the chaotic system that we use is totally controllable, then the poles of the close-loop system may be placed at any desired locations by means of state feedback through an appropriate state feedback gain matrix. The simulating results are shown that the synchronization error reduces to zero as time elapses. In other words, the dynamic error reduces to zero rapidly if the state feedback gain matrix is chosen appropriately.