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Method and apparatus for use of a watermark and a unique time dependent reference for the purpose of copy protection

  • US 6,865,675 B1
  • Filed: 03/25/1999
  • Issued: 03/08/2005
  • Est. Priority Date: 07/14/1998
  • Status: Expired due to Term
First Claim
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1. A method of protecting content transmitted as a stream of data, the method comprising the steps of:

  • determining a checkpoint at a receiving device;

    calculating, at a source device, a time dependent ticket utilizing the checkpoint, wherein a watermark, a ticket, and the checkpoint together indicate a copy protection status of the content;

    transmitting said stream of data, said watermark, said ticket, and said time dependent ticket to said receiving device; and

    comparing said time dependent ticket to a stored checkpoint at said receiving device.

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