Digital watermarks for audio signals

We present a novel technique for embedding digital "watermarks" into digital audio signals. Watermarking is a technique used to label digital media by hiding copyright or other information into the underlying data. The watermark must be imperceptible or undetectable by the user and should be robust to attacks and other types of distortion. In our method, the watermark is generated by filtering a PN-sequence with a filter that approximates the frequency masking characteristics of the human auditory system. It is then weighted in the time domain to account for temporal masking. We discuss the detection of the watermark and assess the robustness of our watermarking approach to attacks and various signal manipulations.