Secure Communication Through a Chaotic System and a Sliding-Mode Observer.

This article presents a secure communication scheme based on chaotic systems using a sliding-mode observer (SMO) that is robust against disturbances affecting the transmitter and transmission process. The original message is first encrypted using a $N$ -cipher with a key signal and then fed into the state equation, whereas the key signal is fed into the output equation. The chaotic system in the transmitter is re-expressed to decouple the disturbances from the signals of interest. An SMO is then designed based on this form and implemented in the receiver to perform synchronization, and recover the broadcast messages to perform secure communication. The conditions required for the SMO to be feasible are investigated in terms of the transmitter system matrices. A set of design procedures for the chaotic secure communication scheme is outlined. Finally, a simulated example is shown to exhibit the efficacy of the proposed scheme. [ABSTRACT FROM AUTHOR]