Chaotic secure communication based on nonlinear autoregressive filter with changeable parameters

This Letter proposes a chaotic secure communication scheme based on nonlinear autoregressive digital filter with changeable parameters, where the nonlinear filter is employed to serve as a high-ordered chaotic dynamic system, the plaintext to be transmitted is modulated into the chaotic signal by chaos shift keying (CSK) approach, and a noncoherent detection with maximum likelihood (ML) method is utilized to recover the original signals from the received noisy signals. In addition, a spread-spectrum (SS) method is adopted to improve the noise performance. Theoretical analyses and simulation results show that the proposed scheme has high security, good noise performance, and is easy implemented by the autoregressive filter structure with changeable parameters.