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Selective encryption to enable multiple decryption keys

  • US 7,233,669 B2
  • Filed: 12/13/2002
  • Issued: 06/19/2007
  • Est. Priority Date: 01/02/2002
  • Status: Active Grant
First Claim
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1. A method of selectively encrypting digital video content, comprising;

  • receiving a plurality of unencrypted packets containing the digital video content;

    selecting certain of the packets of a specified type for encryption according to a selection criterion;

    encrypting the selected packets using a first encryption key to produce first encrypted packets;

    encrypting the selected packets using a second encryption key to produce second encrypted packets;

    wherein the selected packets encrypted using the first encryption key and the selected packets encrypted using the second encryption key contain the same digital video content;

    replacing the unencrypted packets of the specified packet type with the first encrypted packets and the second encrypted packets in the digital video signal to produce a partially dual encrypted video signal comprised of unencrypted packets along with first and second encrypted packets;

    wherein the first encryption key is valid for a first segment of time and the second encryption key is valid for a subsequent time segment; and

    transmitting the partially dual encrypted video signal to a receiver.

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