Communicating with optical hyperchaos: Information encryption and decryption in delayed nonlinear feedback systems

Recent theoretical studies and experimental demonstrations have shown the p ossibility of using chaos for the encryption of message signals in communic ation systems. Chaos is generated by systems with delayed nonlinear feedbac k, which feature hyperchaotic (i.e., of high dimensionality) dynamics. The different ways for the injection of the information in the emitter and the process of the synchronization of the receiver are considered. The analysis of all the possibilities can be used to choose the correct topology of com munication systems and, more generally, to explain the behavior of any chao tic systems ruled by nonlinear difference-differential equations.