Content revocation and license modification in a digital rights management (DRM) system on a computing device

• US 20030187801A1
• Filed: 03/26/2002
• Published: 10/02/2003
• Est. Priority Date: 03/26/2002
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Gajjala, Vijay K., Ganesan, Krishnamurthy, Lafornara, Philip J., Chase, Charlie David Jr., McKune, Jeffrey Richard, Strom, Clifford Paul
• Granted Patent: US 7,080,043 B2
• Time in Patent Office: Days
• US Class Current: 705/59
• CPC Class Codes: G06F 21/1076 Revocation

Abstract

Content revocation is achieved by disabling licenses issued to a computing device for the content. A content revocation is delivered within a license to the computing device. Upon license storage the content revocation is recognized, validated, and stored in a secure state store under the public key of the content server (PU-CS) that issued the content. Each license has a (PU-CS) therein, and each license evaluation considers each content revocation stored in the state store and having the same (PU-CS). The license is disabled or otherwise affected based on the considered content revocation. A content revocation is one form of a license modification that may be delivered within a license.

Claims

1. A method in combination with a digital rights management (DRM) architecture wherein digital content on a computing device is rendered only in accordance with a corresponding digital license on the computing device, the method for modifying the rendering license on the computing device, the method comprising:

generating a modification string containing modification information for modifying the rendering license;

placing the generated modification string in a carrier license; and

issuing the carrier license with the modification string to the computing device;

wherein the computing device stores the carrier license and the modification string, and wherein selecting the rendering license for use in rendering the corresponding content causes the computing device to retrieve the stored modification and act upon the rendering license in accordance with the modification information in the retrieved modification string.

2. The method of claim 1 comprising:

delivering the modification string to a license server;

placing, by the license server, the delivered modification string in a carrier license;

issuing, by the license server, the carrier license with the modification string to the computing device.

3. The method of claim 1 for disabling the rendering license on the computing device, the method comprising:

generating a disabling string containing disabling information for disabling the rendering license;

placing the generated disabling string in a carrier license; and

issuing the carrier license with the disabling string to the computing device.

4. The method of claim 1 comprising generating a modification string containing modification information for modifying the rendering license, an identifying indicia identifying a source of the corresponding content, whereby the rendering license includes the identifying indicia and thereby indexes to such modification string based thereon, and a sequence number employed to determine whether the modification string is more current than another modification string having the same identifying indicia.

5. A digital structure in combination with a digital rights management (DRM) system wherein digital content on a computing device is rendered only in accordance with a corresponding digital license on the computing device, the rendering license including an identifying indicia identifying a source of the corresponding content, the structure being a modification string for modifying the rendering license on the computing device and comprising:

the identifying indicia, whereby the rendering license indexes to such modification string based on such identifying indicia;

a sequence number, whereby such sequence number is employed to determine whether the modification string is more current than another modification string; and

a modification script including a set of instructions to be processed with respect to the rendering license.

6. The structure of claim 5 wherein the identifying indicia is a public key of an owner of the content (PU-CS).

7. The structure of claim 5 wherein the identifying indicia is a public key of an issuer of the rendering license (PU-LS).

8. The structure of claim 5 wherein such modification string is to be placed in a carrier license and the carrier license with the modification string therein is to be issued by an issuer to the computing device, and wherein the identifying indicia is a public key of the issuer of the carrier license (PU-LS).

9. The structure of claim 5 wherein each modification string as issued under a particular identifying indicia is provided with a unique, non-repeating, and non-decreasing sequence number, and as between first and second modification strings having the same identifying indicia and respective sequence numbers, the one of the first and second modification strings having the higher sequence number is more current.

10. The structure of claim 5 wherein the modification script acts to perform an act selected from a group consisting of disabling the rendering license, deleting the rendering license, modifying state information with respect to the rendering license, conditionally disabling the rendering license, conditionally deleting the rendering license, conditionally modifying state information with respect to the rendering license, and combinations thereof.

11. The structure of claim 5 further comprising a digital signature to verify that the modification string originated from an appropriate source.

12. The structure of claim 11 wherein the digital signature is based on a private key of an owner of the content (PR-CS) and is verified based on a corresponding public key of the owner of the content (PU-CS), whereby a party other than the content owner cannot produce the modification string.

13. The structure of claim 11 wherein the digital signature is at least partially based on the modification script.

14. A method in combination with a digital rights management (DRM) architecture wherein digital content on a computing device is rendered only in accordance with a corresponding digital license on the computing device, the method for modifying the rendering license on the computing device, the method comprising:

receiving a carrier license with a modification string therein at the computing device, the modification string containing modification information for modifying the rendering license and an identifying indicia identifying a source of the digital content;

storing the received carrier license in a license store on the computing device; and

processing the modification string in the carrier license by at least conditionally storing the modification string in a secure store on the computing device according to the identifying indicia, whereby the modification string may be retrieved from the secure store according to such identifying indicia.

15. The method of claim 14 comprising receiving the carrier license with the modification string therein non-purposefully.

16. The method of claim 14 comprising periodically obtaining a carrier license as a requirement for continued operation of the DRM architecture at the computing device.

17. The method of claim 14 wherein the carrier license is the rendering license.

18. The method of claim 14 wherein processing the modification string is performed substantially contemporaneously with storing the carrier license.

19. The method of claim 14 wherein the identifying indicia is a public key of an owner of the content (PU-CS).

20. The method of claim 19 wherein the modification string further contains a digital signature based on a private key of the owner of the content (PR-CS) corresponding to (PU-CS), the processing of the modification string further comprising verifying based on (PU-CS) that a party other than the content owner did not produce the modification string.

21. The method of claim 20 wherein the verifying is at least partially based on the modification information in the modification string.

22. The method of claim 14 comprising storing the modification string in the secure store as a value of an attribute, where the identifying indicia is a name of the attribute.

23. The method of claim 14 wherein the modification string further contains a sequence number indicative of how current the modification string is, wherein the secure store may contain only one modification string per identifying indicia, and wherein processing the modification string in the carrier license comprises:

checking the secure store for another modification string corresponding to the identifying indicia of the modification string being processed; and

if such another modification string is present in the secure store;

checking the sequence number of the another modification string and the sequence number of the modification string being processed to determine which is more current; and

storing the modification string being processed and discarding the another modification string only if the modification string being processed is more current.

24. The method of claim 14 wherein the secure store may contain multiple modification strings per identifying indicia, and wherein processing the modification string in the carrier license comprises storing the modification string being processed in the secure store along with any other modification strings having the same identifying indicia.

25. The method of claim 14 further comprising processing the modification information in the modification string in response to a selection of the rendering license for use in rendering the corresponding content.

26. The method of claim 25 comprising processing the modification information to affect only the selected rendering license and not any other rendering license that corresponds to the content.

27. A method in combination with a digital rights management (DRM) architecture wherein digital content on a computing device is rendered only in accordance with a corresponding digital license on the computing device, the method for modifying the rendering license on the computing device, the method comprising:

receiving a modification string containing modification information for modifying the rendering license and an identifying indicia identifying a source of the digital content, and storing the received modification string in a secure store on the computing device according to the identifying indicia thereof;

selecting the rendering license for use in rendering the corresponding content, the rendering license including the identifying indicia;

retrieving the modification string from the secure store based on the identifying indicia thereof matching the identifying indicia of the rendering license; and

acting upon the rendering license in accordance with the modification information in the retrieved modification string.

28. The method of claim 27 wherein the identifying indicia is a public key of an owner of the content (PU-CS).

29. The method of claim 28 wherein the modification string further contains a digital signature based on a private key of the owner of the content (PR-CS) corresponding to (PU-CS), the processing of the modification string further comprising verifying based on (PU-CS) that a party other than the content owner did not produce the modification string.

30. The method of claim 29 wherein the verifying is at least partially based on the modification information in the modification string.

31. The method of claim 27 wherein acting upon the rendering license in accordance with the modification information in the retrieved modification string comprises a member selected from a group consisting of disabling the rendering license, deleting the rendering license, modifying state information with respect to the rendering license, conditionally disabling the rendering license, conditionally deleting the rendering license, conditionally modifying state information with respect to the rendering license, and combinations thereof.

32. The method of claim 27 wherein the rendering license is stored in a license store on the computing device, and wherein acting upon the rendering license in accordance with the modification information in the retrieved modification string comprises deleting the rendering license from the license store.

33. The method of claim 27 wherein acting upon the rendering license in accordance with the modification information in the retrieved modification string comprises disabling the rendering license by placing disabling information regarding such rendering license in the state store, whereby the rendering license may later be re-enabled by another modification string having modification information therein that places enabling information regarding such rendering license in the state store.

34. The method of claim 27 comprising:

receiving a plurality of modification strings, each containing modification information for modifying the rendering license and a common identifying indicia identifying a source of the digital content, and storing each of the received modification strings in a secure store on the computing device according to the common identifying indicia thereof;

selecting the rendering license for use in rendering the corresponding content, the rendering license including the common identifying indicia;

retrieving each of the modification strings from the secure store based on the common identifying indicia thereof matching the identifying indicia of the rendering license; and

acting upon the rendering license in accordance with the modification information in each of the retrieved modification strings.

35. The method of claim 34 wherein each of the modification strings further contains a sequence number indicative of how current the modification string is, and wherein acting upon the rendering license in accordance with the modification information in each of the retrieved modification strings comprises processing each modification string according to the sequence numbers of the revocations strings, earliest to most current.

36. A computer-readable medium having stored thereon computer-executable instructions for performing a method in combination with a digital rights management (DRM) architecture wherein digital content on a computing device is rendered only in accordance with a corresponding digital license on the computing device, the method for modifying the rendering license on the computing device, the method comprising:

generating a modification string containing modification information for modifying the rendering license;

placing the generated modification string in a carrier license; and

issuing the carrier license with the modification string to the computing device;

wherein the computing device stores the carrier license and the modification string, and wherein selecting the rendering license for use in rendering the corresponding content causes the computing device to retrieve the stored modification and act upon the rendering license in accordance with the modification information in the retrieved modification string.

37. The medium of claim 36 wherein the method comprises:

delivering the modification string to a license server;

placing, by the license server, the delivered modification string in a carrier license;

issuing, by the license server, the carrier license with the modification string to the computing device.

38. The medium of claim 36 for disabling the rendering license on the computing device, the method comprising:

generating a disabling string containing disabling information for disabling the rendering license;

placing the generated disabling string in a carrier license; and

issuing the carrier license with the disabling string to the computing device.

39. The medium of claim 36 wherein the method comprises generating a modification string containing modification information for modifying the rendering license, an identifying indicia identifying a source of the corresponding content, whereby the rendering license includes the identifying indicia and thereby indexes to such modification string based thereon, and a sequence number employed to determine whether the modification string is more current than another modification string having the same identifying indicia.

40. A computer-readable medium having stored thereon a digital structure, the digital structure co-acting with a digital rights management (DRM) system wherein digital content on a computing device is rendered only in accordance with a corresponding digital license on the computing device, the rendering license including an identifying indicia identifying a source of the corresponding content, the structure being a modification string for modifying the rendering license on the computing device and comprising:

the identifying indicia, whereby the rendering license indexes to such modification string based on such identifying indicia;

a sequence number, whereby such sequence number is employed to determine whether the modification string is more current than another modification string; and

a modification script including a set of instructions to be processed with respect to the rendering license.

41. The medium of claim 40 wherein the identifying indicia is a public key of an owner of the content (PU-CS).

42. The medium of claim 40 wherein the identifying indicia is a public key of an issuer of the rendering license (PU-LS).

43. The medium of claim 40 wherein such modification string is to be placed in a carrier license and the carrier license with the modification string therein is to be issued by an issuer to the computing device, and wherein the identifying indicia is a public key of the issuer of the carrier license (PU-LS).

44. The medium of claim 40 wherein each modification string as issued under a particular identifying indicia is provided with a unique, non-repeating, and non-decreasing sequence number, and as between first and second modification strings having the same identifying indicia and respective sequence numbers, the one of the first and second modification strings having the higher sequence number is more current.

45. The medium of claim 40 wherein the modification script acts to perform an act selected from a group consisting of disabling the rendering license, deleting the rendering license, modifying state information with respect to the rendering license, conditionally disabling the rendering license, conditionally deleting the rendering license, conditionally modifying state information with respect to the rendering license, and combinations thereof.

46. The medium of claim 40 wherein the structure further comprises a digital signature to verify that the modification string originated from an appropriate source.

47. The medium of claim 46 wherein the digital signature is based on a private key of an owner of the content (PR-CS) and is verified based on a corresponding public key of the owner of the content (PU-CS), whereby a party other than the content owner cannot produce the modification string.

48. The medium of claim 46 wherein the digital signature is at least partially based on the modification script.

49. A computer-readable medium having stored thereon computer-executable instructions for performing a method in combination with a digital rights management (DRM) architecture wherein digital content on a computing device is rendered only in accordance with a corresponding digital license on the computing device, the method for modifying the rendering license on the computing device, the method comprising:

receiving a carrier license with a modification string therein at the computing device, the modification string containing modification information for modifying the rendering license and an identifying indicia identifying a source of the digital content;

storing the received carrier license in a license store on the computing device; and

processing the modification string in the carrier license by at least conditionally storing the modification string in a secure store on the computing device according to the identifying indicia, whereby the modification string may be retrieved from the secure store according to such identifying indicia.

50. The medium of claim 49 wherein the method comprises receiving the carrier license with the modification string therein non-purposefully.

51. The medium of claim 49 wherein the method comprises periodically obtaining a carrier license as a requirement for continued operation of the DRM architecture at the computing device.

52. The medium of claim 49 wherein the carrier license is the rendering license.

53. The medium of claim 49 wherein processing the modification string is performed substantially contemporaneously with storing the carrier license.

54. The medium of claim 49 wherein the identifying indicia is a public key of an owner of the content (PU-CS).

55. The medium of claim 54 wherein the modification string further contains a digital signature based on a private key of the owner of the content (PR-CS) corresponding to (PU-CS), the processing of the modification string further comprising verifying based on (PU-CS) that a party other than the content owner did not produce the modification string.

56. The medium of claim 55 wherein the verifying is at least partially based on the modification information in the modification string.

57. The medium of claim 49 wherein the method comprises storing the modification string in the secure store as a value of an attribute, where the identifying indicia is a name of the attribute.

58. The medium of claim 49 wherein the modification string further contains a sequence number indicative of how current the modification string is, wherein the secure store may contain only one modification string per identifying indicia, and wherein processing the modification string in the carrier license comprises:

checking the secure store for another modification string corresponding to the identifying indicia of the modification string being processed;

if such another modification string is present in the secure store;

checking the sequence number of the another modification string and the sequence number of the modification string being processed to determine which is more current; and

storing the modification string being processed and discarding the another modification string only if the modification string being processed is more current.

59. The medium of claim 49 wherein the secure store may contain multiple modification strings per identifying indicia, and wherein processing the modification string in the carrier license comprises storing the modification string being processed in the secure store along with any other modification strings having the same identifying indicia.

60. The medium of claim 49 wherein the method further comprises processing the modification information in the modification string in response to a selection of the rendering license for use in rendering the corresponding content.

61. The medium of claim 60 wherein the method comprises processing the modification information to affect only the selected rendering license and not any other rendering license that corresponds to the content.

62. A computer-readable medium having stored thereon computer-executable instructions for performing a method in combination with a digital rights management (DRM) architecture wherein digital content on a computing device is rendered only in accordance with a corresponding digital license on the computing device, the method for modifying the rendering license on the computing device, the method comprising:

receiving a modification string containing modification information for modifying the rendering license and an identifying indicia identifying a source of the digital content, and storing the received modification string in a secure store on the computing device according to the identifying indicia thereof;

selecting the rendering license for use in rendering the corresponding content, the rendering license including the identifying indicia;

retrieving the modification string from the secure store based on the identifying indicia thereof matching the identifying indicia of the rendering license; and

acting upon the rendering license in accordance with the modification information in the retrieved modification string.

63. The medium of claim 62 wherein the identifying indicia is a public key of an owner of the content (PU-CS).

64. The medium of claim 63 wherein the modification string further contains a digital signature based on a private key of the owner of the content (PR-CS) corresponding to (PU-CS), the processing of the modification string further comprising verifying based on (PU-CS) that a party other than the content owner did not produce the modification string.

65. The medium of claim 64 wherein the verifying is at least partially based on the modification information in the modification string.

66. The medium of claim 62 wherein acting upon the rendering license in accordance with the modification information in the retrieved modification string comprises a member selected from a group consisting of disabling the rendering license, deleting the rendering license, modifying state information with respect to the rendering license, conditionally disabling the rendering license, conditionally deleting the rendering license, conditionally modifying state information with respect to the rendering license, and combinations thereof.

67. The medium of claim 62 wherein the rendering license is stored in a license store on the computing device, and wherein acting upon the rendering license in accordance with the modification information in the retrieved modification string comprises deleting the rendering license from the license store.

68. The medium of claim 62 wherein acting upon the rendering license in accordance with the modification information in the retrieved modification string comprises disabling the rendering license by placing disabling information regarding such rendering license in the state store, whereby the rendering license may later be re-enabled by another modification string having modification information therein that places enabling information regarding such rendering license in the state store.

69. The medium of claim 62 wherein the method comprises:

receiving a plurality of modification strings, each containing modification information for modifying the rendering license and a common identifying indicia identifying a source of the digital content, and storing each of the received modification strings in a secure store on the computing device according to the common identifying indicia thereof;

selecting the rendering license for use in rendering the corresponding content, the rendering license including the common identifying indicia;

retrieving each of the modification strings from the secure store based on the common identifying indicia thereof matching the identifying indicia of the rendering license; and

acting upon the rendering license in accordance with the modification information in each of the retrieved modification strings.

70. The medium of claim 69 wherein each of the modification strings further contains a sequence number indicative of how current the modification string is, and wherein acting upon the rendering license in accordance with the modification information in each of the retrieved modification strings comprises processing each modification string according to the sequence numbers of the revocations strings, earliest to most current.