关键词: 异步保密通信, 自适应, 抗噪声, 动态时滞, 超混沌

Abstract: Aiming at the high security requirements of non real-time communication and the noise existed in channel, an adaptive asynchronous anti-noise secure communication scheme based on chaotic masking-modulation was proposed. Four pseudo-random vectors of state variables were generated by hyper-chaotic Lorenz system, which were adjusted to an identical interval by their signal gains. Two vectors, which were generated by the PieceWise Linear Chaotic Map (PWLCM), were applied to randomly select and determine the step length of dynamic delay in the four state variables to generate the carrier signal. Finally, the pre-encoded binary message was marked into the carrier signal in pairs and sent out after being added Gaussain noise. Experimental results reveal that the ratio of the minimum signal magnification factor to noise coefficient lies within a small interval of [0.08, 0.11], if the ratio is set beyond the upper limit of the interval, the Bit Error Rate (BER) can be ensured to reach zero, so the masked signal can be perfectly recovered by the receiver under channel noise. The nonlinear dynamical character of hyper-chaotic system was used to implement adaptively asynchronous secure communication with channel noise, the numerical simulation demonstrates the effectiveness of the secure communication scheme.

Key words: asynchronous secure communication, adaptive, anti-noise, dynamical delay, hyper-chaos