摘要 |
<p>A system for the protecting against use of pirated music. Two watermarks (18) are inserted into the music to be protected by the music publisher. One watermark is robust -- it will not be destroyed by compression. The other watermark is weak -- it is designed to be destroyed by compression. The presence of the watermarks are detected at a compression screener module (20). The robust mark tells a player that the music is protected, i.e., that it is not authorized to be delivered in compressed form over an insecure channel. If the music is found to have been compressed and it was delivered over an insecure channel, then its play or other processing can be restricted. A watermark detector (26) may check digital signals for the presence of the watermarks and enforce the system logic.</p> |