An improved secure communication scheme based passive synchronization of hyperchaotic complex nonlinear system

In this paper, an improved secure communication scheme is proposed based on passive synchronization of hyperchaotic complex nonlinear system. The hyperchaotic complex Lü system is employed to encrypt the emitted signal. Comparing with the existing approaches, the useful information in our work can be unbounded. In the transmitter, the original information signal is modulated into one parameter of hyperchaotic complex Lü system and it is assumed that the parameter of the receiver system is unknown. In the receiver, based on the passivity theory, the controllers and corresponding parameter update rule are designed to make two identical hyperchaotic complex Lü systems asymptotically synchronized, and identify the unknown parameter simultaneously. The information signal can be recovered accurately by the estimated parameter. Corresponding theoretical proofs and numerical simulations demonstrate the feasibility and effectiveness of the proposed method. It is also shown that the presented secure communication scheme is robust against different channel noise.