Speaker verification security improvement by means of speech watermarking

This paper presents a security enhanced speaker verification system based on speech signal watermarking. Our proposed system can detect several situations where a playback speech, a synthetically generated speech, a manipulated speech signal or a hacker trying to imitate the speech is fooling the biometric system. In addition, we have generated a watermarked speech signals database from which we have obtained relevant conclusions about the influence of this technique on speaker verification rates. Mainly we have checked that biometrics and watermarking can coexist simultaneously minimizing the mutual effects. Experimental results show that the proposed speech watermarking system can suffer A-law coding with a message error rate lower than 2 × 10−4 for SWR higher than 20 dB at a message rate of 48 bits/s.