Synchronization of hyperchaotic systems with multiple unknown parameters and its application in secure communication

Based on the Lyapunov stability theory, synchronization between the hyperchaotic Chen systems is achieved by designing linear feedback controllers, and parameters of the master can be identified exactly via the update laws, even though they are unknown in advance. Then a secure communication scheme of parameter modulation via the synchronization of hyperchaotic systems is proposed. The modulation scheme is to modulate each bit of information into the parameters of master system, and the state variables of hyperchaotic systems are transmitted through the public channel. The transmitted signals are random-like, so it is not easy to be extracted by the intruders. Meanwhile, information can be recovered successfully by adaptive mechanisms in the receiver side. Finally, some security analyses of scheme are discussed. The proposed scheme is robust with respect to noise to some extent, and return maps of the transmitted signals are also provided to show the high security.