A playback attack detector for speaker verification systems

A playback attack detector (PAD), which can be mobilized in guarding speaker verification systems against playback attacks, is described in this paper. To detect playback attacks, the PAD uses a feature set called peakmap, which includes the frame and FFT bin numbers of the five highest spectral peaks from each of the voiced frames in an utterance. During the detection, the peakmap of the incoming recording is first extracted and then compared to those of all the other recordings that are stored at the system end. Each comparison will yield a similarity score that represents the level of similarity between the two recordings. The incoming recording is declared to be a playback recording if its maximum similarity score is above a threshold.