An approach to resist blind source separation attacks of speech signals

Recently, there has been great interest in the physical layer security technique which exploits the artificial noise (AN) to enlarge the channel condition between the legitimate receiver and the eavesdropper. However, in certain communication scenery, this strategy may suffer from some attacks in the signal processing perspective. In this paper, we consider speech signals and the scenario in which the eavesdropper has the similar channel performance compared to the legitimate receiver. We design the optimal artificial noise (AN) to resist the attack of the eavesdropper who uses the blind source separation (BSS) technology to reconstruct the secret information. The Optimal AN is obtained by making a tradeoff between results of direct eavesdropping and reconstruction. The simulation results show that the AN we proposed has better performance than that of the white Gaussian AN to resist the BSS attacks effectively.