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Elementary bitstream cryptographic material transport systems and methods

  • US 9,706,259 B2
  • Filed: 08/28/2015
  • Issued: 07/11/2017
  • Est. Priority Date: 12/04/2009
  • Status: Active Grant
First Claim
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1. A method of playing back encrypted video on a playback device, where encrypted video data is contained within a container file and can be extracted and decrypted to create an elementary bitstream, the method comprising:

  • extracting at least partially encrypted video data from a container file to create an at least partially encrypted elementary bitstream using a demultiplexer, where at least a portion of the at least partially encrypted elementary bitstream is encrypted by a frame key;

    selecting a heuristic from a predetermined set of heuristics using the demultiplexer;

    generating key material for a wrap key using the selected heuristic using the demultiplexer;

    encrypting the frame key with the wrap key using the demultiplexer;

    inserting the encrypted frame key into the at least partially encrypted elementary bitstream using the demultiplexer;

    encrypting a synchronization payload with the wrap key using the demultiplexer, wherein the synchronization payload includes contents known to the demultiplexer and the decoder;

    providing the encrypted synchronization payload, and the combined at least partially encrypted elementary bitstream and encrypted frame key, to a video decoder;

    extracting the encrypted frame key from the at least partially encrypted elementary bitstream using the video decoder;

    decrypting the contents of the encrypted synchronization payload using a heuristic identified to match the selected heuristic using the video decoder;

    generating a copy of the wrap key using the identified correct heuristic using the video decoder;

    decrypting the encrypted frame key using the copy of the wrap key and the video decoder;

    decrypting at least a portion of the at least partially encrypted elementary bitstream using the decrypted frame key and the video decoder; and

    decoding the decrypted portion of the elementary bitstream for rendering on a display device using the video decoder.

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