Rendering digital content in an encrypted rights-protected form

• US 20060212363A1
• Filed: 02/13/2006
• Published: 09/21/2006
• Est. Priority Date: 03/27/1999
• Status: Abandoned Application

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Bell, Jeffrey R.C., Jones, Thomas C., England, Paul, Peinado, Marcus, Blinn, Arnold N., Jakubowski, Mariusz H., Abburi, Rajasekhar, Manferdelli, John L., Yu, Hai Ying (Vincent), Venkatesan, Ramaranthnam
• Application Number:
  US11/353,321
• Publication Number:
  US 20060212363A1
• Time in Patent Office: Days
• US Class Current: 705/26
• CPC Class Codes: G06F 21/109 by using specially-adapted hardware at the client
• CPC Class Codes: G06F 21/71 to assure secure computing or processing of information
• CPC Class Codes: G06F 21/84 output devices, e.g. displays or monitors
• CPC Class Codes: G06F 2211/007 Encryption, En-/decode, En-/decipher, En-/decypher, Scramble, (De-)compress
• CPC Class Codes: G06F 2221/2105 Dual mode as a secondary aspect
• CPC Class Codes: G06F 2221/2137 Time limited access, e.g. to a computer or data
• CPC Class Codes: G06Q 30/06 Buying, selling or leasing transactions
• CPC Class Codes: G06Q 30/0601 Electronic shopping [e-shopping]
• CPC Class Codes: G07F 9/002 Vending machines being part of a centrally controlled network of vending machines
• CPC Class Codes: H04L 2463/101 applying security measures for digital rights management data processing systems or methods, specially adapted for commerce, e.g. marketing, shopping, billing, auctions or e-commerce G06Q30/00
• CPC Class Codes: H04L 63/0442 wherein the sending and receiving network entities apply asymmetric encryption, i.e. different keys for encryption and decryption cryptographic mechanisms or cryptographic arrangements for public-key encryption H04L9/30
• CPC Class Codes: H04L 63/068 using time-dependent keys, e.g. periodically changing keys cryptographic mechanisms or cryptographic arrangements for controlling usage of secret information H04L9/088
• CPC Class Codes: H04L 63/0823 using certificates cryptographic mechanisms or cryptographic arrangements for entity authentication involving certificates H04L9/3263
• CPC Class Codes: H04L 63/12 Applying verification of the received information cryptographic mechanisms or cryptographic arrangements for data integrity or data verification H04L9/32

Abstract

To render digital content determined to be in an encrypted rights-protected form, each available license corresponding to the digital content to be rendered is identified, where each such license includes a decryption key (KD) for decrypting the digital content to be rendered, and where the decryption key (KD) in the license is encrypted according to a public key (PU) (PU(KD)). One of the identified licenses is selected and (KD) is obtained from the selected license by obtaining (PU(KD)) from the selected license and decrypting (PU(KD)) according to a private key (PR) corresponding to (PU) to produce (KD). The digital content is decrypted with (KD), and the decrypted digital content is provided for actual rendering.

Claims

1. A method for rendering digital content determined to be in an encrypted rights-protected form, the method comprising:

invoking, by the rendering application, a Digital Rights Management (DRM) system having a public key (PU) and a corresponding private key (PR), the DRM system having access to at least one stored digital license, each license corresponding to a piece of digital content and including a decryption key (KD) for decrypting the corresponding digital content, the decryption key (KD) in the license being encrypted according to the public key (PU) of the DRM system (PU(KD));

identifying, by the DRM system, each license corresponding to the digital content to be rendered;

selecting, by the DRM system, one of the identified licenses;

obtaining, by the DRM system, (KD) from the selected license by obtaining (PU(KD)) from the selected license and decrypting (PU(KD)) according to (PR) to produce (KD);

decrypting, by the DRM system, the digital content with (KD); and

providing, by the DRM system, the decrypted digital content to the rendering application for actual rendering.

2. The method of claim 1 further comprising, after invoking the DRM system:

firstly calling, by the rendering application, the DRM system; and

ceding, by the rendering application, control to the DRM system.

3. The method of claim 2 further comprising, after selecting a license and before decrypting the digital content with (KD):

returning, by the DRM system, control to the rendering application;

secondly calling, by the rendering application, the DRM system to decrypt the encrypted digital content; and

authenticating, by the DRM system, the rendering application.

4. The method of claim 3 wherein firstly calling the DRM system includes passing, by the rendering application, a first identification of such rendering application to the DRM system, wherein secondly calling the DRM system includes passing, by the rendering application, a second identification of such rendering application to the DRM system, and wherein authenticating the rendering application includes verifying that the first identification is the same as second identification.

5. The method of claim 1 further comprising authenticating, by the DRM system, the rendering application.

6. The method of claim 1 wherein the digital content is sought to be rendered in a particular manner, and wherein selecting one of the licenses further comprises determining whether each corresponding license provides the right to render the digital content in the manner sought.

7. The method of claim 6 further comprising passing, by the rendering application, the particular manner that the digital content is sought to be rendered to the DRM system.

8. The method of claim 1 further comprising, after invoking the DRM system, calling, by the rendering application, the DRM system to decrypt the encrypted digital content.

9. The method of claim 1 wherein identifying each license corresponding to the digital content to be rendered comprises acquiring, by the DRM system, a license corresponding to the digital content from a license source if no such license is found.

10. The method of claim 9 wherein the acquiring of the license comprises acquiring the license from a remote license server by way of a communications network.

11. The method of claim 1 wherein the digital content includes a content ID, wherein each license includes a content ID of the digital content corresponding thereto, and wherein identifying each license corresponding to the digital content comprises searching for each license having the content ID of the digital content.

12. The method of claim 1 wherein the decryption key (KD) in the license being encrypted according to the public key (PU) of the DRM system (PU(KD)) comprises the license including (PU) encrypting an intermediate value (Z) to result in (PU(Z)) and the intermediate value (Z) protecting the decryption key (KD) to result in (Z(KD)), the method comprising obtaining, by the DRM system, (KD) from the selected license by obtaining (PU(Z)) and (Z(KD)) from the selected license, decrypting (PU(Z)) according to (PR) to produce (Z), and employing (Z) to derive (KD) from (Z(KD)).

13. The method of claim 12 wherein the intermediate value (Z) protecting the decryption key (KD) to result in (Z(KD)) in the license comprises a value (DZ) encrypting (KD) to result in (DZ(KD)), the value (DZ) being derived from (Z), the method comprising obtaining, by the DRM system, (KD) from the selected license by obtaining (PU(Z)) and (DZ(KD)) from the selected license, decrypting (PU(Z)) according to (PR) to produce (Z), employing (Z) to derive (DZ), and decrypting (DZ(KD)) according to (DZ) to result in (KD).

14. A method for rendering digital content determined to be in an encrypted rights-protected form, the method comprising:

identifying each available license corresponding to the digital content to be rendered, each such license including a decryption key (KD) for decrypting the digital content to be rendered, the decryption key (KD) in the license being encrypted according to a public key (PU) (PU(KD));

selecting one of the identified licenses;

obtaining (KD) from the selected license by obtaining (PU(KD)) from the selected license and decrypting (PU(KD)) according to a private key (PR) corresponding to (PU) to produce (KD);

decrypting the digital content with (KD); and

providing the decrypted digital content for actual rendering.

15. The method of claim 14 wherein the digital content is sought to be rendered in a particular manner, and wherein selecting one of the licenses further comprises determining whether each corresponding license provides the right to render the digital content in the manner sought.

16. The method of claim 14 wherein identifying each license corresponding to the digital content to be rendered comprises acquiring a license corresponding to the digital content from a license source if no such license is found.

17. The method of claim 16 wherein the acquiring of the license comprises acquiring the license from a remote license server by way of a communications network.

18. The method of claim 14 wherein the digital content includes a content ID, wherein each license includes a content ID of the digital content corresponding thereto, and wherein identifying each license corresponding to the digital content comprises searching for each license having the content ID of the digital content.

19. The method of claim 14 wherein the decryption key (KD) in the license being encrypted according to the public key (PU) (PU(KD)) comprises the license including (PU) encrypting an intermediate value (Z) to result in (PU(Z)) and the intermediate value (Z) protecting the decryption key (KD) to result in (Z(KD)), the method comprising obtaining (KD) from the selected license by obtaining (PU(Z)) and (Z(KD)) from the selected license, decrypting (PU(Z)) according to (PR) to produce (Z), and employing (Z) to derive (KD) from (Z(KD)).

20. The method of claim 19 wherein the intermediate value (Z) protecting the decryption key (KD) to result in (Z(KD)) in the license comprises a value (DZ) encrypting (KD) to result in (DZ(KD)), the value (DZ) being derived from (Z), the method comprising obtaining (KD) from the selected license by obtaining (PU(Z)) and (DZ(KD)) from the selected license, decrypting (PU(Z)) according to (PR) to produce (Z), employing (Z) to derive (DZ), and decrypting (DZ(KD)) according to (DZ) to result in (KD).