Federated digital rights management scheme including trusted systems

  • US 9,184,920 B2
  • Filed: 02/18/2014
  • Issued: 11/10/2015
  • Est. Priority Date: 03/14/2006
  • Status: Active Grant
First Claim
Patent Images

1. A method of decoding encrypted content using a playback device on which an active user encryption key is stored, where the content includes frames of video and at least a portion of a plurality of frames of video are encrypted using at least one frame encryption key, and the at least one frame encryption key is encrypted using a content encryption key, and one or more copies of the content encryption key are each encrypted using one or more user encryption keys including the active user encryption key, the method comprising:

  • obtaining encrypted content using a playback device, where the content includes frames of video and at least a portion of a plurality of frames of video are encrypted using at least one frame encryption key;

    obtaining using the playback device a copy of the at least one frame encryption key that is encrypted using a content encryption key and obtaining one or more copies of the content encryption key that are each encrypted using one or more user encryption keys including an active user encryption key stored on the playback device;

    decrypting one of the one or more copies of the content encryption key using the playback device and the active user encryption key; and

    playing back frames of the encrypted content using the playback device, where playing back frames of the encrypted content further comprises;

    identifying any portions of a frame that are encrypted;

    identifying the frame encryption key used to encrypt the identified portions of the frame;

    decrypting the identified frame encryption key using the decrypted content encryption key;

    decrypting the encrypted portions of the frame using the decrypted identified frame encryption key; and

    decoding the unencrypted frame of video.

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