Identifying material stored using a signature as a retrieval index

摘要

A method of identifying material which includes the step of inserting an identifying code into a signal as a watermark, and deriving a signature from the material. The code and signature are stored in a database. The watermarked signal may be distributed and/or transmitted through a network. The signal may be processed in the network. A monitor derives from the received signal, the signature and the code. The derived signature and the derived code are compared with the stored signature and code to check the provenance of the material. The watermark contains an authorization code allowing duplication of the material.