RELEASING DECRYPTED DIGITAL CONTENT TO AN AUTHENTICATED PATH

• US 20080021839A1
• Filed: 10/02/2007
• Published: 01/24/2008
• Est. Priority Date: 01/14/2000
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Yerrace, Frank, England, Paul, Peinado, Marcus
• Granted Patent: US 8,744,969 B2
• Time in Patent Office: Days
• US Class Current: 705/59
• CPC Class Codes: G06F 21/10 Protecting distributed programs or content, e.g. vending or licensing of copyrighted material protection in video systems or pay television H04N7/16 ; Digital rights management [DRM]
• CPC Class Codes: G06F 2221/2107 File encryption

Abstract

Digital content is released to a rendering application for forwarding by such rendering application to an ultimate destination by way of a path therebetween. The path is defined by at least one module, and the digital content is initially in an encrypted form. An authentication of at least a portion of the path is performed to determine whether each defining module thereof is to be trusted to appropriately handle the digital content passing therethrough. The encrypted digital content is decrypted if in fact each such defining module is to be trusted, and the decrypted digital content is forwarded to the rendering application for further forwarding to the ultimate destination by way of the authenticated path.

Claims

1. A digital rights management system that releases encrypted digital content to a rendering application that forwards the digital content to an ultimate destination by way of a path therebetween, the path being defined by at least one module, comprising:

a black box that performs an authentication of at least a portion of the path to determine whether each defining module thereof is to be trusted to appropriately handle the digital content passing therethrough, wherein said black box is programmed to perform authentication by;

traversing the at least a portion of the path to develop a map of each module in the path;

authenticating each module in the map; and

for each module in the at least a portion of the path, receiving from the module a certificate as issued by a certifying authority, determining from the received certificate whether such received certificate is acceptable for purposes of authenticating the module, checking a revocation list to ensure that the received certificate has not been revoked, and refusing to decrypt the encrypted digital content if at least one module in the at least a portion of the path fails to provide an acceptable certificate,

wherein said black box decrypts the encrypted digital content if in fact each such defining module is to be trusted; and

means for forwarding the decrypted digital content to the rendering application for further forwarding to the ultimate destination by way of the authenticated path,

2. The system of claim 1 wherein the path includes a user mode portion and a kernel portion, further comprising:

means for scrambling the digital content upon such digital content being outputted from the rendering application to the path such that the scrambled digital content enters the user mode portion of the path, such scrambled digital content then passing through the modules that define the user mode portion of the path and transiting from the user mode portion to the kernel portion of the path.

3. The system of claim 2 wherein the path comprises a de-scrambling module that de-scrambles the scrambled digital content upon such scrambled digital content transiting from the user mode portion to the kernel portion.

4. The system of claim 3 wherein the de-scrambling module is in the kernel portion of the path.

5. The system of claim 4 wherein the black box performs an authentication of at least a portion of the kernel portion of the path to determine whether each defining module thereof is to be trusted to appropriately handle the digital content passing therethrough.

6. The system of claim 1 wherein the path includes a user mode portion and a kernel portion, and the black box performs an authentication of at least a portion of the kernel portion of the path to determine whether each defining module thereof is to be trusted to appropriately handle the digital content passing therethrough.

7. The system of claim 6 further comprising means for scrambling the digital content upon such digital content being outputted from the rendering application to the path such that the scrambled digital content enters the user mode portion of the path, such scrambled digital content then passing through the modules that define the user mode portion of the path and transiting from the user mode portion to the kernel portion of the path.

8. The system of claim 7 wherein the path comprises a de-scrambling module that de-scrambles the scrambled digital content upon such scrambled digital content transiting from the user mode portion to the kernel portion.

9. The system of claim 8 wherein the de-scrambling module is in the kernel portion of the path.

10. The system of claim 1 wherein the black box ignores each module not in the map.

11. The system of claim 1 wherein said black box is further programmed to perform authentication by:

authenticating an initial module;

determining all first destination modules that receive data from said initial module;

authenticating each said first destination module;

determining all second destination modules that receive data from each such first destination module;

iteratively repeating the authenticating and determining steps for additional destination modules until each module in such at least a portion of the path has been determined and authenticated.

12. The system of claim 11 wherein said black box authenticates the initial module by authenticating a module in the at least a portion of the path that is to receive the digital content before any other module in the at least a portion of the path, whereby the initial module leads to fully determining all other modules that define the at least a portion of the path.

13. The system of claim 11 further comprising a database device that keeps track of all modules determined to be in the at least a portion of the path, whereby already-determined modules in the at least a portion of the path can be recognized.

14. The system of claim 1 further comprising a certifying authority that provides the revocation list and a secure storage device that stores the received revocation list.

15. The system of claim 1 wherein the black box decrypts the encrypted digital content if all the modules in the at least a portion of the path provide an acceptable certificate.

16. The system of claim 1 wherein the black box is further programmed to perform authentication, for each module in the at least a portion of the path that fails to provide an acceptable certificate, by:

defining a sub-portion of the path including the non-providing module;

scrambling the digital content upon such digital content entering the sub-portion of the path, such scrambled digital content then passing through the modules that define the sub-portion of the path;

de-scrambling the scrambled digital content upon such scrambled digital content exiting from the sub-portion of the path; and

declaring the sub-portion trustworthy.

17. The system of claim 1 wherein the path includes a user mode portion and a kernel portion, and the black box performs an authentication of the user mode portion of the path and of the kernel portion of the path to determine whether each defining module thereof is to be trusted to appropriately handle the digital content passing therethrough.

18. The system of claim 1 wherein the path includes a tunneled portion, further comprising:

means for scrambling the digital content upon such digital content entering the tunneled portion of the path, such scrambled digital content then passing through the modules that define the tunneled portion of the path; and

means for de-scrambling the scrambled digital content upon such scrambled digital content exiting from the tunneled portion of the path,

wherein said black box authenticates at least a portion of the path external to the tunneled portion of the path to determine whether each defining module thereof is to be trusted to appropriately handle the digital content passing therethrough, whereby an authentication of the tunneled portion is unnecessary.

19. The system of claim 18 wherein the path includes a user mode portion, a kernel portion, and a tunneled portion in the user mode portion, wherein:

the scrambling means scrambles the digital content upon such digital content entering the tunneled portion of the user mode portion of the path, such scrambled digital content then passing through the modules that define the tunneled portion of the user mode portion of the path; and

the scrambling means de-scrambling the scrambled digital content upon such scrambled digital content exiting from the tunneled portion of the user mode portion of the path,

wherein said black box authenticates at least a portion of the path external to the tunneled portion of the user mode portion of the path to determine whether each defining module thereof is to be trusted to appropriately handle the digital content passing therethrough, whereby an authentication of the tunneled portion is unnecessary.