METHOD AND SYSTEM FOR ENSURING SEQUENTIAL PLAYBACK OF DIGITAL MEDIA

• US 20150310190A1
• Filed: 07/06/2015
• Published: 10/29/2015
• Est. Priority Date: 09/30/2008
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: LINDAHL, Aram, JAMES, Bryan J.
• Granted Patent: US 10,268,806 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 21/107 License processing; Key processing
• CPC Class Codes: H04L 2209/603 Digital right managament [DRM]
• CPC Class Codes: H04L 9/08 Key distribution or management, e.g. generation, sharing or updating, of cryptographic keys or passwords network architectures or network communication protocols for supporting key management in a packet data network H04L63/06
• CPC Class Codes: H04L 9/0861 Generation of secret information including derivation or calculation of cryptographic keys or passwords
• CPC Class Codes: H04L 9/0891 Revocation or update of secret information, e.g. encryption key update or rekeying

Abstract

Techniques for ensuring that media playback proceeds sequentially through media content of a digital media asset are disclosed. In one embodiment, distinct portions (e.g., segments) of a digital media asset can be separately encrypted such that on playback decoded data being output from at least one prior portion can be used to derive a cryptographic key that is used in decrypting a subsequent portion of the digital media asset.

Claims

1. A method for requiring a media asset to be played back sequentially, the method comprising:

dividing the media asset into a plurality of segments;

generating corresponding encryption keys for the plurality of segments, wherein, when a segment is not a first segment of the plurality of segments, the corresponding encryption key is based in part on a previous segment;

encrypting the plurality of segments in accordance with the corresponding encryption keys to produce a plurality of encrypted segments;

generating decryption information for decrypting the plurality of encrypted segments;

combining a first encryption key that corresponds to the first segment, the plurality of encrypted segments, and the decryption information to produce a protected media asset; and

storing the protected media asset.

2. The method of claim 1, further comprising, in response to receiving, from a client device, a request for the media asset:

providing the protected media asset to a client device, wherein the decryption information enables the client device to decrypt the plurality of encrypted segments.

3. The method of claim 2, further comprising, prior to providing the protected media asset to the client device:

encrypting the protected media asset using a master key; and

providing the master key to the client device.

4. The method of claim 1, wherein the decryption information indicates a starting encrypted segment and an ending encrypted segment within the plurality of encrypted segments.

5. The method of claim 4, wherein the decryption information indicates that the first encryption key corresponds to the starting segment.

6. The method of claim 1, further comprising:

identifying the media asset to be encrypted.

7. The method of claim 6, wherein the corresponding encryption keys for the plurality of segments are generated in accordance with an encryption algorithm that is pre-determined or randomly determined.

8. A non-transitory computer readable storage medium configured to store instructions that, when executed by a processor included in a computing device, cause the computing device to carry out steps that include:

dividing a media asset into a plurality of segments;

generating corresponding encryption keys for the plurality of segments, wherein, when a segment is not a first segment of the plurality of segments, the corresponding encryption key is based in part on a previous segment;

encrypting the plurality of segments in accordance with the corresponding encryption keys to produce a plurality of encrypted segments;

generating decryption information for decrypting the plurality of encrypted segments;

combining a first encryption key that corresponds to the first segment, the plurality of encrypted segments, and the decryption information to produce a protected media asset; and

storing the protected media asset.

9. The non-transitory computer readable storage medium of claim 8, wherein the steps further include, in response to receiving, from a client device, a request for the media asset:

providing the protected media asset to a client device, wherein the decryption information enables the client device to decrypt the plurality of encrypted segments.

10. The non-transitory computer readable storage medium of claim 9, wherein the steps further include, prior to providing the protected media asset to the client device:

encrypting the protected media asset using a master key; and

providing the master key to the client device.

11. The non-transitory computer readable storage medium of claim 8, wherein the decryption information indicates a starting encrypted segment and an ending encrypted segment within the plurality of encrypted segments.

12. The non-transitory computer readable storage medium of claim 11, wherein the decryption information indicates that the first encryption key corresponds to the starting segment.

13. The non-transitory computer readable storage medium of claim 8, wherein the steps further include:

identifying the media asset to be encrypted.

14. The non-transitory computer readable storage medium of claim 13, wherein the corresponding encryption keys for the plurality of segments are generated in accordance with an encryption algorithm that is pre-determined or randomly determined.

15. A computing device, comprising:

a processor configured to cause the computing device to carry out steps that include;

dividing a media asset into a plurality of segments;

generating corresponding encryption keys for the plurality of segments, wherein, when a segment is not a first segment of the plurality of segments, the corresponding encryption key is based in part on a previous segment;

encrypting the plurality of segments in accordance with the corresponding encryption keys to produce a plurality of encrypted segments;

generating decryption information for decrypting the plurality of encrypted segments;

combining a first encryption key that corresponds to the first segment, the plurality of encrypted segments, and the decryption information to produce a protected media asset; and

storing the protected media asset.

16. The computing device of claim 15, wherein the steps further include, in response to receiving, from a client device, a request for the media asset:

providing the protected media asset to a client device, wherein the decryption information enables the client device to decrypt the plurality of encrypted segments.

17. The computing device of claim 16, wherein the steps further include, prior to providing the protected media asset to the client device:

encrypting the protected media asset using a master key; and

providing the master key to the client device.

18. The computing device of claim 15, wherein the decryption information indicates a starting encrypted segment and an ending encrypted segment within the plurality of encrypted segments.

19. The computing device of claim 18, wherein the decryption information indicates that the first encryption key corresponds to the starting segment.

20. The computing device of claim 15, wherein the corresponding encryption keys for the plurality of segments are generated in accordance with an encryption algorithm that is pre-determined or randomly determined.