IDENTIFYING MATERIAL

摘要

A method of identifying material comprises the step of inserting (882) an identifying code (886) into a signal as a watermark, and deriving (884) a signature from the material. The code and signature are stored in a database (894). The watermarked signal may be distributed and/or transmitted through a network (888). The signal may be processed in the network. A monitor (890) derives from the received signal, the signature and the code. They are compared (892) with the stored signature and code to check the provenance of the material.