Systems and Methods for Playing Back Alternative Streams of Protected Content Protected Using Common Cryptographic Information

• US 20130061045A1
• Filed: 12/29/2011
• Published: 03/07/2013
• Est. Priority Date: 09/01/2011
• Status: Active Grant

• Current Assignee: Sonic IP Incorporated (Endeavor Group Holdings Inc.)
• Original Assignee: DivX, LLC (f/k/a DivX CF Holdings LLC) (SoftBank Group Corp.)
• Inventors: Kiefer, Michael George, Grab, Eric William, Braness, Jason
• Granted Patent: US 8,909,922 B2
• Time in Patent Office: Days
• US Class Current: 713/160
• CPC Class Codes: H04L 2209/603 Digital right managament [DRM]
• CPC Class Codes: H04L 63/0428 wherein the data content is protected, e.g. by encrypting or encapsulating the payload
• CPC Class Codes: H04L 9/0819 Key transport or distribution, i.e. key establishment techniques where one party creates or otherwise obtains a secret value, and securely transfers it to the other(s) network architectures or network communication protocols for key distribution in a packet data network H04L63/062
• CPC Class Codes: H04L 9/0822 using key encryption key
• CPC Class Codes: H04L 9/0861 Generation of secret information including derivation or calculation of cryptographic keys or passwords
• CPC Class Codes: H04L 9/14 using a plurality of keys or algorithms
• CPC Class Codes: H04L 9/32 including means for verifying the identity or authority of a user of the system or for message authentication, e.g. authorization, entity authentication, data integrity or data verification, non-repudiation, key authentication or verification of credentials
• CPC Class Codes: H04N 21/2347 involving video stream encryption
• CPC Class Codes: H04N 21/2541 Rights Management protecting software against unauthorised usage in a vending or licensing environment G06F21/10; security in data switching network management H04L41/28; security management or policies for network security H04L63/20; access security in wireless networks H04W12/08
• CPC Class Codes: H04N 21/4408 involving video stream encryption, e.g. re-encrypting a decrypted video stream for redistribution in a home network
• CPC Class Codes: H04N 21/4627 Rights management associated to the content security in data switching network management H04L41/28; security management or policies for network security H04L63/20; access security in wireless networks H04W12/08
• CPC Class Codes: H04N 21/6334 for authorisation, e.g. by transmitting a key wireless communications network key management H04W12/04; wireless communications network access security H04W12/08
• CPC Class Codes: H04N 21/64715 Protecting content from unauthorized alteration within the network verifying the information received for network security in communication control or processing H04L63/12; integrity in wireless network security H04W12/10

Abstract

Systems and methods for performing adaptive bitrate streaming using alternative streams of protected content in accordance with embodiments of the invention are described. One embodiment of the invention includes a processor, and memory containing a client application. In addition, the client application configures the processor to: request a top level index file identifying a plurality of alternative streams of protected content, where each of the alternative streams of protected content are encrypted using common cryptographic information; obtain the common cryptographic information; request portions of content from at least the plurality of alternative streams of protected content; access the protected content using the common cryptographic information; and playback the content.

Claims

1. A playback device, comprising:

a processor;

memory containing a client application;

wherein the client application configures the processor to;

request a top level index file identifying a plurality of alternative streams of protected content, where each of the alternative streams of protected content are encrypted using common cryptographic information;

obtain the common cryptographic information;

request portions of content from at least the plurality of alternative streams of protected content;

access the protected content using the common cryptographic information; and

playback the content.

2. The playback device of claim 1, wherein:

the alternative streams of protected content are alternative streams of protected video;

each of the alternative streams of protected video includes DRM information indicating portions of frames of video that are encrypted and identifying at least a portion of the common cryptographic information used to access the encrypted portions of the frames of video; and

the client application configures the processor to;

obtain a protected frame of video from one of the alternative streams of protected video;

obtain DRM information indicating a portion of the protected frame of video that is encrypted;

identify at least a portion of the common cryptographic information that is used to access the encrypted portion of the protected frame using the DRM information;

decrypt the encrypted portion of the protected frame of video using the identified portion of the common cryptographic information; and

decode the frame of video.

3. The playback device of claim 1, wherein:

each of the alternative streams of protected content is contained within a separate container file; and

the top level index file identifies a container file containing each of the alternative streams.

4. The playback device of claim 3, wherein:

the container files containing each of the alternative streams of protected content comprise at least one header including the common cryptographic information and information that describes the encoding of the stream of protected content; and

the top level index file identifies the location of the at least one header within each container file.

5. The playback device of claim 4, wherein the common cryptographic information is a set of encryption keys.

6. The playback device of claim 5, wherein:

the common set of encryption keys is encrypted; and

the client application configures the processor to securely receive cryptographic information used to unencrypt the common set of encryption keys.

7. The playback device of claim 4, wherein the client application configures the processor to obtain the common cryptographic information by requesting at least one header of a container file identified in the top level index file.

8. The playback device of claim 7, wherein:

each container file containing one of the alternative streams of protected content further comprises an index; and

the client application configures the processor to request a portion of content from one of the container files by configuring the processor to;

request at least a portion of an index from the container file;

identify the portion of the container file containing a specific portion of content using the index; and

request the identified portion of the container file.

9. The playback device of claim 4, wherein the container files are Matroska container files.

10. The playback device of claim 9, wherein the common cryptographic information is stored in a common DRM Header element contained within a Tracks element within each of the Matroska container files containing the alternative streams of protected content.

11. The playback device of claim 10, wherein:

the common cryptographic information is a set of encryption keys; and

the set of encryption keys is encrypted and stored within the DRM Header element.

12. The playback device of claim 11, wherein the client application configures the processor to:

obtain cryptographic information that can be used to unencrypt the set of encryption keys stored within the DRM Header element; and

unencrypt the set of encryption keys stored within the DRM Header element using the obtained cryptographic information.

13. The playback device of claim 10, wherein the client application configures the processor to obtain the DRM Header element by requesting a Tracks element from one of the Matroska container files identified in the top level index file.

14. The playback device of claim 13, wherein:

each Mastroska container file containing an alternative stream of protected content further comprises an index contained within a Cues element; and

the client application configures the processor to request a portion of content from one of the Matroska container files by configuring the processor to;

request at least a portion of a Cues element from a Matroska container file containing one of the alternative streams of protected content;

identify a portion of the Matroska container file containing a specific portion of content using at least one CueTrackPosition element within the Cues element; and

request the portion of the Matroska container file identified by the at least one CueTrackPosition element.

15. The playback device of claim 14, wherein the index comprises a plurality of CueTrackPosition elements that identify the location of a plurality of Cluster elements within the Matroska container file.

16. The playback device of claim 15, wherein:

each Cluster element contains a plurality of BlockGroup elements including encoded portions of content;

a CueTrack Position element indexes each Cluster element; and

each CueTrackPosition element includes the size of the Cluster element that it indexes.

17. The playback device of claim 14, wherein

the alternative streams of protected content are alternative streams of protected video;

each of the Matroska container files containing an alternative stream of protected video includes a DRMInfo element in a BlockGroup element containing a protected frame of video, where the DRMInfo element indicates at least a portion of the protected frames of video that is encrypted and identifies at least a portion of the common cryptographic information used to access the at least one encrypted portion of the protected frame of video; and

the client application configures the processor to access video frames in a stream of protected video using the common cryptographic information by configuring the processor to;

obtain a BlockGroup containing a protected frame of video;

parse the BlockGroup element to obtain a DRMInfo element indicating at least a portion of the protected frame of video that is encrypted using an encryption key from the set of encryption keys;

decrypt the at least one encrypted portion of the protected frame of video using the identified encryption key; and

decode the frame of video.

18. A method of performing adaptive bitrate streaming using a plurality of alternative streams of protected content, where each of the streams of protected content is protected using common cryptographic information, the method comprising:

requesting a top level index file identifying a plurality of alternative streams of protected content using a playback device, where each of the alternative streams of protected content are encrypted using common cryptographic information;

obtaining the common cryptographic information using the playback device;

requesting portions of content from at least the plurality of alternative streams of protected content using the playback device;

accessing the protected content using the playback device and the common cryptographic information; and

playing back the content using the playback device.

19. The method of claim 18, wherein:

the alternative streams of protected content are alternative streams of protected video;

each of the alternative streams of protected video includes DRM information indicating portions of frames of video that are encrypted and identifying at least a portion of the common cryptographic information used to access the encrypted portions of the frames of video; and

the method further comprises;

obtaining a protected frame of video from one of the alternative streams of protected video using the playback device;

obtaining DRM information indicating a portion of the protected frame of video that is encrypted using the playback device;

identify at least a portion of the common cryptographic information that is used to access the encrypted portion of the protected frame using the playback device and the DRM information;

decrypting the encrypted portion of the protected frame of video using the playback device and the identified portion of the common cryptographic information; and

decoding the frame of video using the playback device.

20. The method of claim 18, wherein:

each of the alternative streams of protected content is contained within a separate container file; and

the top level index file identifies a container file containing each of the alternative streams.

21. The method of claim 20, wherein:

the container files containing each of the alternative streams of protected content comprise at least one header including the common cryptographic information and information that describes the encoding of the stream of protected content; and

the top level index file identifies the location of the at least one header within each container file.

22. The method of claim 21, wherein the common cryptographic information is a set of encryption keys.

23. The method of claim 22, wherein:

the set of encryption keys is encrypted so that it is accessible using cryptographic information obtained by the playback device; and

the method further comprising obtaining cryptographic information using the playback device.

24. The method of claim 23, wherein

the set of encryption keys is encrypted using at least one encryption key;

and

the playback device securely obtains the at least one encryption key.

25. The method of claim 24, wherein the at least one encryption key is encrypted using at least one encryption key included in the cryptographic information bound to the playback device.

26. The method of claim 23, further comprising obtaining the common cryptographic information by requesting at least one header of a container file identified in the top level index file using the playback device.

27. The method of claim 26, wherein:

each container file containing one of the alternative streams of protected content further comprises an index; and

the method further comprising;

requesting at least a portion of an index from the container file using the playback device;

identify the portion of the container file containing a specific portion of content using the playback device and the index; and

requesting the identified portion of the container file using the playback device.

28. The method of claim 21, wherein the container files are Matroska container files.

29. The method of claim 28, wherein the common cryptographic information is stored in a common DRM Header element contained within a Tracks element within each of the Matroska container files containing the alternative streams of protected content.

30. The method of claim 29, wherein:

the common cryptographic information is a set of encryption keys; and

the set of encryption keys is encrypted and stored within the DRM Header element.

31. The method of claim 30, wherein:

the set of encryption keys is encrypted so that it is accessible using cryptographic information obtained by the playback device; and

the method further comprising obtaining cryptographic information using the playback device.

32. The method of claim 30, further comprising obtaining the DRM Header element by requesting a Tracks element from one of the Matroska container files identified in the top level index file.

33. The method of claim 32, wherein:

each Mastroska container file containing an alternative stream of protected content further comprises an index contained within a Cues element; and

the method further comprises;

requesting at least a portion of a Cues element from a Matroska container file containing one of the alternative streams of protected content using the playback device;

identifying a portion of the Matroska container file containing a specific portion of content using the playback device and at least one CueTrackPosition element within the Cues element; and

requesting the portion of the Matroska container file identified by the at least one CueTrackPosition element.

34. The method of claim 33, wherein the index comprises a plurality of CueTrackPosition elements that identify the location of a plurality of Cluster elements within the Matroska container file.

35. The method of claim 34, wherein:

each Cluster element contains a plurality of BlockGroup elements including encoded portions of content;

a CueTrack Position element indexes each Cluster element; and

each CueTrackPosition element includes the size of the Cluster element that it indexes.

36. The method of claim 33, wherein

the alternative streams of protected content are alternative streams of protected video;

each of the Matroska container files containing an alternative stream of protected video includes a DRMInfo element in a BlockGroup element containing a protected frame of video, where the DRMInfo element indicates at least a portion of the protected frames of video that is encrypted and identifies at least a portion of the common cryptographic information used to access the at least one encrypted portion of the protected frame of video; and

the method further comprising;

obtaining a BlockGroup containing a protected frame of video using the playback device;

parsing the BlockGroup element to obtain a DRMInfo element indicating at least a portion of the protected frame of video that is encrypted using the playback device and an encryption key from the set of encryption keys;

decrypting the at least one encrypted portion of the protected frame of video using the playback device and the identified encryption key; and

decoding the frame of video using the playback device.

37. A machine readable medium containing processor instructions, where execution of the instructions by a processor causes the processor to perform a process comprising:

request a top level index file identifying a plurality of alternative streams of protected content, where each of the alternative streams of protected content are encrypted using common cryptographic information;

obtaining the common cryptographic information;

requesting portions of content from at least the plurality of alternative streams of protected content;

accessing the protected content using the common cryptographic information; and

playing back the content.

38. The machine readable medium of claim 37, wherein:

the alternative streams of protected content are alternative streams of protected video;

each of the alternative streams of protected video includes DRM information indicating portions of frames of video that are encrypted and identifying at least a portion of the common cryptographic information used to access the encrypted portions of the frames of video; and

execution of the instructions by a processor also causes the processor to perform a process comprising;

obtaining a protected frame of video from one of the alternative streams of protected video;

obtaining DRM information indicating a portion of the protected frame of video that is encrypted;

identify at least a portion of the common cryptographic information that is used to access the encrypted portion of the protected frame using the DRM information;

decrypting the encrypted portion of the protected frame of video using and the identified portion of the common cryptographic information; and

decoding the frame of video.

39. The machine readable medium of claim 37, wherein the machine readable medium is non-volatile memory.