Playback devices and methods for playing back alternative streams of content protected using a common set of cryptographic keys

• US 10,225,588 B2
• Filed: 09/19/2018
• Issued: 03/05/2019
• Est. Priority Date: 09/01/2011
• Status: Active Grant

• Current Assignee: DivX, LLC (f/k/a DivX CF Holdings LLC) (SoftBank Group Corp.)
• Original Assignee: DivX, LLC (f/k/a DivX CF Holdings LLC) (SoftBank Group Corp.)
• Inventors: Kiefer, Michael George, Grab, Eric William, Braness, Jason
• Primary Examiner(s): Getachew, Abiy
• Application Number:
  US16/136,183
• Publication Number:
  US 20190020907A1
• Time in Patent Office: 167 Days
• 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 for playing protected content from a plurality of alternative streams, comprising:

a set of one or more processors; and

a non-volatile storage containing an application for causing the set of one or more processors to perform the steps of;

obtaining a top level index file identifying a plurality of alternative streams of protected video, wherein each of the alternative streams of protected video includes partially encrypted video frames that are encrypted using a set of common keys comprising at least one key, and wherein the partially encrypted video frames contain encrypted portions and unencrypted portions of data;

obtaining a copy of the set of common keys;

detecting streaming conditions for the playback device;

selecting a stream from the plurality of alternative streams of protected video based on the detected streaming conditions;

receiving a container index that provides byte ranges for portions of the selected stream of protected video within an associated container file;

requesting portions of the selected stream of protected video based on the provided byte ranges;

locating encryption information that identifies encrypted portions of frames of video within the requested portions of the selected stream of protected video;

decrypting each encrypted portion of the frames of video identified within the located encryption information using the set of common keys; and

playing back the decrypted frames of video obtained from the requested portions of the selected stream of protected video.

2. The playback device of claim 1, wherein the step of requesting portions of the selected stream further comprises the step of obtaining a container file containing protected video from at least one of the plurality of alternative streams, where the container file also includes encryption information that identifies portions of frames of video that are encrypted and a reference to at least one key from the set of common keys to utilize in accessing the encrypted portions of the frames of video.

3. The playback device of claim 1, wherein the located encryption information comprises a reference to the start of an encrypted block of data.

4. The playback device of claim 3, wherein the located encryption information further comprises the size of the encrypted block of data.

5. The playback device of claim 3, wherein the located encryption information further comprises cryptographic information that can be utilized to access the encrypted portion of the frame.

6. The playback device of claim 5, wherein the cryptographic information is a reference to at least one key from the set of common keys.

7. The playback device of claim 1, wherein the application is further for causing the set of processors to perform the steps of:

detecting a change in the streaming conditions;

identifying a second alternative stream of protected video based on the detected change;

receiving a container index that provides byte ranges for portions of the second alternative stream of protected video within a second associated container file;

requesting portions of the second alternative stream of protected video based on the provided byte ranges;

decrypting each encrypted portion of the frames of video from the requested portions of the second alternative stream of protected video using the set of common keys; and

playing back the decrypted frames of video from the requested portions of the second alternative stream of protected video.

8. The playback device of claim 1, wherein the application is further for causing the set of processors to perform the steps of:

transmitting a request for content to a set of one or more content distribution servers; and

receiving the content from the set of one or more content distribution servers.

9. The playback device of claim 8, wherein the application is further for causing the set of processors to perform the steps of:

transmitting a request for cryptographic information including the set of common keys to a set of one or more DRM servers; and

receiving the cryptographic information from the set of one or more DRM servers.

10. The playback device of claim 1, wherein the application is further for causing the set of processors to perform the step of obtaining the container index from at least one file selected from the group consisting of:

the associated container file containing the selected stream of protected content; and

a separate file to the associated container file containing the selected stream of protected content.

11. The playback device of claim 1, wherein the common set of keys comprises a plurality of keys.

23. The playback device of claim 1, wherein:

the container index is part of a hierarchical index; and

the application is further for causing the set of processors to perform the step of;

obtaining a lower layer index that identifies the location of frames within a specific requested portion of the selected stream of protected video; and

identify partially encrypted video frames from within the specific requested portion of the selected stream using the lower layer index.

12. A method for playing protected content from a plurality of alternative streams on a playback device, the method comprising:

obtaining a top level index file identifying a plurality of alternative streams of protected video, wherein each of the alternative streams of protected video includes partially encrypted video frames that are encrypted using a set of common keys comprising at least one key, and wherein the partially encrypted video frames contain encrypted portions and unencrypted portions of data;

obtaining a copy of the set of common keys;

detecting streaming conditions for the playback device;

selecting a stream from the plurality of alternative streams of protected video based on the detected streaming conditions;

receiving a container index that provides byte ranges for portions of the selected stream of protected video within an associated container file;

requesting portions of the selected stream of protected video based on the provided byte ranges;

locating encryption information that identifies encrypted portions of frames of video within the requested portions of the selected stream of protected video;

decrypting each encrypted portion of the frames of video identified within the located encryption information using the set of common keys; and

playing back the decrypted frames of video obtained from the requested portions of the selected stream of protected video using a decoder.

13. The method of claim 12, wherein requesting portions of the selected stream further comprises obtaining a container file containing protected video from at least one of the plurality of alternative streams, where the container file also includes encryption information that identifies portions of frames of video that are encrypted and a reference to at least one key from the set of common keys to utilize in accessing the encrypted portions of the frames of video.

14. The method of claim 12, wherein the located encryption information comprises a reference to the start of an encrypted block of data.

15. The method of claim 14, wherein the located encryption information further comprises the size of the encrypted block of data.

16. The method of claim 14, wherein the located encryption information further comprises cryptographic information that can be utilized to access the encrypted portion of the frame.

17. The method of claim 16, wherein the cryptographic information is a reference to at least one key from the set of common keys.

18. The method of claim 12 further comprising:

detecting a change in the streaming conditions;

identifying a second alternative stream of protected video based on the detected change;

receiving a container index that provides byte ranges for portions of the second alternative stream of protected video within a second associated container file;

requesting portions of the second alternative stream of protected video based on the provided byte ranges;

decrypting each encrypted portion of the frames of video from the requested portions of the second alternative stream of protected video using the set of common keys; and

playing back the decrypted frames of video from the requested portions of the second alternative stream of protected video.

19. The method of claim 12 further comprising:

transmitting a request for content to a set of one or more content distribution servers; and

receiving the content from the set of one or more content distribution servers.

20. The method of claim 19 further comprising:

transmitting a request for cryptographic information including the set of common keys to a set of one or more DRM servers; and

receiving the cryptographic information from the set of one or more DRM servers.

21. The method of claim 12 further comprising obtaining the container index from at least one file selected from the group consisting of:

the associated container file containing the selected stream of protected content; and

a separate file to the associated container file containing the selected stream of protected content.

22. The method of claim 12, wherein the common set of keys comprises a plurality of keys.

24. The method of claim 12, wherein:

the container index is part of a hierarchical index; and

the method further comprises;

obtaining a lower layer index that identifies the location of frames within a specific requested portion of the selected stream of protected video; and

identify partially encrypted video frames from within the specific requested portion of the selected stream using the lower layer index.