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Encryption and content control in a digital broadcast system

  • US 7,218,738 B2
  • Filed: 10/18/2002
  • Issued: 05/15/2007
  • Est. Priority Date: 01/02/2002
  • Status: Active Grant
First Claim
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1. A selective encryption method, comprising:

  • examining unencrypted packets of data in a digital video signal to identify a specified packet type;

    duplicating the packets of the specified packet type to produce duplicate packets;

    identifying the duplicate packets by a first packet identifier (PID);

    identifying remaining unencrypted packets by a second packet identifier (PID);

    replacing the packets of the specified packet type with the first duplicate packets;

    generating identifying information that identifies the first duplicate packets, and the unencrypted packets;

    storing the identifying information as transport program specific information (PSI);

    creating a data stream comprising the PSI, the first duplicate packets, and the unencrypted packets into the data stream; and

    sending the data stream to a primary encryption encoder.

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