Authentication of signals using watermarks

Abstract

A method of determining if at least a portion of a suspect signal (58) is derived from a watermarked original signal (56) includes the steps of providing a watermark (50) and creating the watermarked original signal (56) by incorporating the watermark (50) onto an original signal (52). At least one first watermark indicator is generated (64) based on the the watermarked original signal (56) and the watermark (50) and at least one second watermark indicator is generated (62) based on the suspect signal (58) and the watermark (50). A determination is made (66, 68, 70) whether at least a portion of the suspect signal (58) is derived from the watermarked original signal (56) is made based on the at least one first watermark indicator (64) and the at least one second watermark indicator (62).

Dependencies are inferred from the claim text.