摘要 |
A copyright protection system for protecting content wherein a receiver dependent ticket is calculated at a source device by combining a receiver dependent identifier with a ticket. The receiver dependent identifier is transmitted from the receiver to the source device prior to the source device transmitting watermarked content to the receiver. The receiver dependent identifier is also stored at the receiver. Thereafter, the source device transmits, to the receiver, watermarked content, the ticket, and the receiver dependent ticket. At the receiver, the stored receiver dependent identifier is combined with the ticket in the same way that the receiver dependent identifier is combined with the ticket at the source device. A result of the combination is compared to the receiver dependent ticket and if the result equals the receiver dependent ticket, then the watermark and ticket may be compared in the usual way to determine the copy protection status of the copy protected content.
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