An inversion approach for chaos-based secure digital communications

A new approach to real-time digital secure speech communication is proposed based on the inversion theory of nonlinear discrete-time dynamical systems. The proposed approach uses an observable minimal-phase nonlinear discrete-time dynamical system, particularly with chaotic zero-dynamics, as the drive system to generate encrypted message signals for transmission. The receiver is the minimal left-inverse system of the drive system with the capability of synchronization. The receiver decrypts the received signal, recovers the original message in real-time. The effectiveness of the proposed approach and design is demonstrated via several examples for secure speech signals transmission. Performance evaluation of the designed secure communication system is discussed. Both analysis and simulation show that the new scheme is secure, simple, accurate and robust.