Scalable, error resilient DRM for scalable media

• US 20040196972A1
• Filed: 04/01/2003
• Published: 10/07/2004
• Est. Priority Date: 04/01/2003
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Zhu, Bin, Li, Shipeng, Yuan, Chun
• Granted Patent: US 7,313,814 B2
• Time in Patent Office: Days
• US Class Current: 380/45
• CPC Class Codes: G06Q 20/382 insuring higher security of transaction
• CPC Class Codes: H04L 2209/603 Digital right managament [DRM]
• CPC Class Codes: H04L 9/06 the encryption apparatus using shift registers or memories for block-wise or stream coding, e.g. DES systems or RC4; Hash functions; Pseudorandom sequence generators
• CPC Class Codes: H04N 19/34 Scalability techniques involving progressive bit-plane based encoding of the enhancement layer, e.g. fine granular scalability [FGS]
• CPC Class Codes: H04N 19/68 involving the insertion of resynchronisation markers into the bitstream
• CPC Class Codes: H04N 21/234327 by decomposing into layers, e.g. base layer and one or more enhancement layers
• CPC Class Codes: H04N 21/23476 by partially encrypting, e.g. encrypting the ending portion of a movie
• CPC Class Codes: H04N 21/440227 by decomposing into layers, e.g. base layer and one or more enhancement layers
• CPC Class Codes: H04N 21/44055 by partially decrypting, e.g. decrypting a video stream that has been partially encrypted
• 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 21/631 Multimode Transmission, e.g. transmitting basic layers and enhancement layers of the content over different transmission paths or transmitting with different error corrections, different keys or with different transmission protocols
• CPC Class Codes: H04N 7/1675 Providing digital key or authorisation information for generation or regeneration of the scrambling sequence pseudo-random number generators in general G06F7/58

Abstract

An exemplary digital rights management engine and related methods divides multimedia content into service level layers, encrypts at least some of the layers, and offers access to the encrypted layers by permission. The multimedia content may be layered using multiple different layering approaches simultaneously, and access to the different types of layers may be offered simultaneously. One of the layers may be left unencrypted to allow free browsing of a low quality service level. An exemplary system of key management for digital rights management is also disclosed.

Claims

1. A method, comprising:

dividing a multimedia content into separate quality layers;

encrypting at least some of the quality layers using a separate secret for each quality layer encrypted; and

granting permission to access an encrypted quality layer by revealing the secret of the encrypted quality layer.

2. The method as recited in claim 1, further comprising simultaneously dividing the multimedia content into multiple sets of separate quality layers.

3. The method as recited in claim 2, wherein one of the multiple sets of separate quality layers comprises peak signal-to-noise ratios (PSNR).

4. The method as recited in claim 2, wherein one of the multiple sets of separate quality layers comprises bitrates.

5. The method as recited in claim 2, wherein one of the multiple sets of separate quality layers comprises frame sizes.

6. The method as recited in claim 2, wherein one of the multiple sets of separate quality layers comprises frame rates.

7. The method as recited in claim 2, wherein one of the multiple sets of separate quality layers comprises color depths.

8. The method as recited in claim 2, wherein one of the multiple sets of separate quality layers comprises quantity of audio channels.

9. The method as recited in claim 2, wherein one of the multiple sets of separate quality layers comprises sampling rates.

10. The method as recited in claim 2, wherein one of the multiple sets of separate quality layers comprises frequency bands.

11. The method as recited in claim 2, wherein one of the multiple sets of separate quality layers comprises audio sample resolutions.

12. The method as recited in claim 1, wherein the permission is a license specific to the encrypted quality layer.

13. The method as recited in claim 1, wherein the multimedia content is a MPEG-4 FGS bitstream.

14. The method as recited in claim 1, wherein the multimedia content uses a SMART or SMART++scalable media adaptation and robust transport coding technology.

15. The method as recited in claim 1, further comprising leaving one or more of the quality layers unencrypted for access without the permission.

16. The method as recited in claim 15, wherein the base layer of the MPEG-4 FGS bitstream is left unencrypted and the enhancement layer of the 6 MPEG-4 FGS bitstream is divided into the quality layers.

17. The method as recited in claim 16, wherein the quality layers are 9 groups of adjacent bit planes and bitrate groups.

18. The method as recited in claim 17, wherein each group of adjacent 12 bit planes is a peak signal-to-noise ratio (PSNR) service level and each bitrate group is a bitrate service level.

19. The method as recited in claim 18, further comprising simultaneously granting permissions to access PSNR service levels and bitrate service levels.

20. The method as recited in claim 1, further comprising rate shaping the encrypted quality layers without decryption.

21. The method as recited in claim 1, further comprising providing a user with all the multimedia content and providing a key to access one of the quality layers without downloading multimedia content.

22. An apparatus, comprising:

a means for dividing a multimedia content into quality layers;

a means for encrypting at least some of the quality layers using a separate key for each quality layer encrypted; and

a means for granting access to a key to decrypt a quality layer.

23. The apparatus as recited in claim 22, wherein the multimedia content is a MPEG-4 FGS bitstream.

24. The apparatus as recited in claim 22, wherein the multimedia content is an audio-visual representation using SMART or SMART++scalable media adaptation and robust transport coding technology.

25. The apparatus as recited in claim 22, wherein the means for dividing is a service level generator to divide an enhancement layer of the multimedia content bitstream into quality layers by bit plane and by bitrate, wherein each quality layer can be accessed simultaneously as both a peak signal-to-noise ratio (PSNR) service level and a bitrate service level.

30. The apparatus as recited in claim 22, wherein the means for encrypting uses a block cipher.

31. The apparatus as recited in claim 30, wherein the block cipher is one of DES, AES, and RC5.

32. The apparatus as recited in claim 31, wherein the block cipher uses an electronic codebook mode (ECB), a block chaining mode (CBC), or an offset codebook (OCB) mode.

40. The apparatus as recited in claim 22, wherein the means for granting access is a service level access grantor to receive a request for a key and to reveal the key.

41. The apparatus as recited in claim 40, wherein the service level access grantor is deployed in a license server.

42. The apparatus as recited in claim 41, wherein the apparatus is deployed in a multimedia content server except the service level access grantor.

43. The apparatus as recited in claim 22, further comprising a bimodal service controller, wherein the bimodal service controller simultaneously administers a peak signal-to-noise ratio service and a bitrate service.

44. The apparatus as recited in claim 22, further comprising a service controller to simultaneously administer a combination of quality layer sets, wherein each quality layer set is selected from a group of quality layer sets consisting of a peak signal-to-noise ratios (PSNR) quality layer set, a bitrate quality layer set, a frame size quality layer set, a frame rate quality layer set, a color depth quality layer set, a quantity of audio channel quality layer set, a sampling rate quality layer set, a frequency band quality layer set, and an audio sample resolution quality layer set.

26. The apparatus as recited in 22, wherein the means for encrypting is an encryption engine using universal block chaining with sum primitive.

27. The apparatus as recited in 22, wherein the means for encrypting in an encryption engine using weak CBC encryption and a summing step.

28. The apparatus as recited in 22, wherein the means for encrypting uses a stream cipher.

29. The apparatus as recited in claim 28, wherein the stream cipher is RC4.

33. The apparatus as recited in 22, wherein the means for encrypting uses C&

S encryption.

34. The apparatus as recited in claim 33, wherein the C&

S encryption includes replacing RC4 encryption with a generic stream cipher.

35. The apparatus as recited in claim 33, wherein the C&

S encryption includes replacing DES encryption of the pre-message authentication code with RC5 encryption.

36. The apparatus as recited in claim 33, wherein the C&

S encryption includes replacing DES encryption of the pre-message authentication code with AES encryption.

37. The apparatus as recited in claim 33, wherein the C&

S encryption uses a reversible message authentication code to replace part of data in the content to be encrypted.

38. The apparatus as recited in claim 37, wherein the message authentication code and an encryption key are used with a stream cipher to encrypt the data.

39. The apparatus as recited in claim 38, wherein a stream cipher key depends on both the encryption key and a hash value of the data to be encrypted.

45. One or more computer readable media containing instructions that are executable by a computer to perform actions comprising:

dividing multimedia content into separate quality layers;

encrypting at least some of the quality layers using a separate key for each quality layer to be encrypted; and

granting a license to use a key to decrypt one of the quality layers.

46. The one or more computer readable media as recited in claim 45, wherein the dividing is accomplished by grouping adjacent bit planes of the multimedia content into peak signal-to-noise ratio service levels.

47. The one or more computer readable media as recited in claim 45, wherein the dividing is accomplished by selecting bitrate service levels.

48. The one or more computer readable media as recited in claim 47, wherein the dividing is accomplished based on one of frame size, frame rate, color depth, quantity of audio channels, sampling rate, frequency band, and audio sample resolution.

49. The one or more computer readable media as recited in claim 48, further comprising instructions that are executable by a computer to perform the action of simultaneously granting licenses to access PSNR service levels and bitrate service levels.

50. The one or more computer readable media as recited in claim 49, further comprising instructions that are executable by a computer to perform the action of simultaneously granting licenses to access service levels based on frame size, frame rate, color depth, quantity of audio channels, sampling rate, frequency band, and audio sample resolution.

51. The one or more computer readable media as recited in claim 50, further comprising instructions that are executable by a computer to perform the action of simultaneously administering PSNR quality layer content for the PSNR service levels and bitrate quality layer content for the bitrate service levels.

52. The one or more computer readable media as recited in claim 51, further comprising instructions that are executable by a computer to perform the action of simultaneously administering quality layer content for the service levels corresponding to frame size, frame rate, color depth, quantity of audio channels, sampling rate, frequency band, and audio sample resolution

53. The one or more computer readable media as recited in claim 45, further comprising instructions that are executable by a computer to perform the action of leaving one of the quality layers unencrypted for access without a key.

54. The one or more computer readable media as recited in claim 45, further comprising instructions that are executable by a computer to perform the action of downloading the difference between a lower quality layer and a higher quality layer when a user already has a key to decrypt the lower quality layer and receives a key to decrypt the higher quality layer.

55. The one or more computer readable media as recited in claim 45, wherein the encrypting allows rate shaping of a quality layer without decrypting the quality layer.

56. A method of key management, comprising:

dividing a scalable multimedia content into two or more quality layer sets, wherein each quality layer set includes quality layers ranging from a lower quality to a higher quality and wherein a first quantity of quality layers in a first quality layer set multiplied by a second quantity of quality layers in a second quality layer set defines a number of content segments;

encrypting at least some of the quality layers; and

assigning a separate key to each of the segments.

57. The method as recited in claim 56, wherein a first key from a lower quality layer in a quality layer set can be derived from a second key of the next higher quality layer in the quality layer set.

58. The method as recited in claim 57, wherein the first key is derived from the second key by hashing at least part of the second key.

59. The method as recited in claim 56, further comprising simultaneously using a first set of keys for the first quality layer set and a second set of keys for the second quality layer set.

60. The method as recited in claim 59, wherein a content segment defined by multiple quality layer sets may be decrypted by using a key from only one of the multiple quality layer sets.

61. The method as recited in claim 56, wherein a first independent random key is generated for the highest quality layer in the first quality layer set and a second independent random key is generated for the highest quality layer in the second quality layer set.

62. The method as recited in claim 61, wherein keys for quality layers lower than the highest quality layers in the first quality layer set and the second quality layer set are generated by securely hashing a key of the next higher quality layer in the respective first and second quality layer sets.

63. The method as recited in claim 56, further comprising:

generating a set of keys for each quality layer set, wherein one key is generated for each quality layer in each quality layer set; and

applying to each of the segments a threshold encryption scheme using keys from the sets of keys, wherein at most one key from each set of keys is used.

64. The method as recited in claim 63, wherein the threshold scheme is a (1, n)-threshold encryption scheme, where n is a number of sets of keys.

65. The method as recited in claim 56, further comprising:

generating a first set of keys for the quality layers in the first quality layer set;

generating a second set of keys for the quality layers in the second quality layer set; and

applying to each of the segments a threshold encryption scheme using a first key from the first set of keys and a second key from the second set of keys.

66. The method as recited in claim 65, wherein the threshold scheme is a (1, 2)-threshold encryption scheme.

67. The method as recited in claim 66, further comprising using one of the keys from the first and second sets of keys to decrypt a segment.

68. The method as recited in claim 56, wherein each of the two or more quality layer sets is selected from a group of quality layer sets consisting of a peak signal-to-noise ratios (PSNR) quality layer set, a bitrate quality layer set, a frame size quality layer set, a frame rate quality layer set, a color depth quality layer set, a quantity of audio channel quality layer set, a sampling rate quality layer set, a frequency band quality layer set, and an audio sample resolution quality layer set.