Unknown input observer based chaotic secure communication

Based on the idea of unknown input observers (UIOs), this Letter considers the problem of chaos secure communication within the master-slave configuration. The unknown constant disturbance of parameters in chaotic systems and the unknown input in chaotic signals can be regarded as messages to be recovered in the slave end. If certain conditions are satisfied, we can recover all the unknown messages by designing the UIO based slave. Theoretical analysis and simulation results fully verify the effectiveness of the proposed scheme. (C) 2007 Elsevier B.V. All rights reserved.