Enforcement of playback count in secure hardware for presentation of digital productions

• US 20050022019A1
• Filed: 07/05/2003
• Published: 01/27/2005
• Est. Priority Date: 07/05/2003
• Status: Abandoned Application

• Current Assignee: General Instrument Corporation (CommScope Holding Company, Inc.)
• Original Assignee: General Instrument Corporation (CommScope Holding Company, Inc.)
• Inventors: Medvinsky, Alexander, Sprunk, Eric
• Application Number:
  US10/613,868
• Publication Number:
  US 20050022019A1
• Time in Patent Office: Days
• US Class Current: 726/4
• 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 2221/2135 Metering
• CPC Class Codes: G11B 20/00086 Circuits for prevention of unauthorised reproduction or copying, e.g. piracy indicating unauthorised use of record carriers in general G11B23/28; scrambling for television signal recording H04N5/913; network architectures or network protocols for network security H04L63/00; cryptographic mechanisms or cryptographic arrangements for secret or secure communication H04L9/00
• CPC Class Codes: G11B 20/00753 wherein the usage restriction limits the number of copies that can be made, e.g. CGMS, SCMS, or CCI flags
• CPC Class Codes: G11B 20/0084 wherein the usage restriction can be expressed as a specific time or date
• CPC Class Codes: G11B 20/00869 wherein the remote server can deliver the content to a receiving device
• CPC Class Codes: G11B 2220/2545 CDs
• CPC Class Codes: H04L 2209/56 Financial cryptography, e.g. electronic payment or e-cash
• CPC Class Codes: H04L 2209/603 Digital right managament [DRM]
• CPC Class Codes: H04L 9/32 including means for verifying the identity or authority of a user of the system or for message authentication, e.g. authorization, entity authentication, data integrity or data verification, non-repudiation, key authentication or verification of credentials
• CPC Class Codes: H04N 21/254 Management at additional data server, e.g. shopping server, rights management server arrangements for maintenance or administration in data networks H04L41/00; network services using third party service providers H04L67/53
• CPC Class Codes: H04N 21/2541 Rights Management protecting software against unauthorised usage in a vending or licensing environment G06F21/10; 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 21/4405 involving video stream decryption
• CPC Class Codes: H04N 21/44204 Monitoring of content usage, e.g. the number of times a movie has been viewed, copied or the amount which has been watched monitoring of user activities for profile generation for accessing a video database G06F16/739; protecting generic digital content where the protection is independent of the precise nature of the content G06F21/10; arrangements for monitoring the use made of the broadcast services in broadcast systems H04H60/31
• 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 21/835 Generation of protective data, e.g. certificates protecting software against unauthorised usage in a vending or licensing environment G06F21/10
• CPC Class Codes: H04N 21/8355 involving usage data, e.g. number of copies or viewings allowed

Abstract

A system for restricting playback of an electronic presentation, such as a digital video or song. The system uses a playback time limit that specifies a duration of allowable playback time. The playback time limit is typically longer than the running time of the presentation so that a user is able to use standard transport controls such as pause, stop, rewind, fast forward, etc., that affect the overall playback time needed to view the presentation in its entirety. One approach uses a secure time base that is provided by a server over a network to a client device that includes a playback device. The secure time base is received and used by secure processing within the playback device. This approach allows rendering of the presentation to an output device to be performed by non-secure processing without unduly compromising the security of the system.

Claims

1. A method of limiting playback of an electronic presentation, wherein a playback device is used to play back the electronic presentation, the method comprising

obtaining a playback time limit for the playback device, wherein the playback time limit is used to restrict playback of the electronic presentation according to a measure of actual cumulative time of the electronic presentation by the playback device.

2. The method of claim 1, wherein the playback time limit is provided in a content license transferred via a network to the playback device.

3. The method of claim 1, wherein the playback time limit is derived from a running time of the electronic presentation.

4. The method of claim 3, wherein the playback time limit is longer than the running time of the electronic presentation.

5. The method of claim 1, wherein a default playback time limit is derived.

6. The method of claim 5, wherein the default playback time limit is derived from a computation.

7. The method of claim 6, wherein the default playback time limit is derived by multiplying a running time of the electronic presentation by 1.75.

8. The method of claim 5, wherein the default playback time limit is derived from a stored value.

9. The method of claim 1, wherein the playback device includes a server that provides streamed content.

10. The method of claim 1, wherein the actual cumulative time does not include intervals where playback is stopped.

11. The method of claim 1, further comprising

obtaining a “

number of plays”

limit at the playback device, wherein the number of plays limit is used with the playback time limit to restrict playback of the electronic presentation by the playback device.

12. The method of claim 1, wherein the playback device includes both secure and non-secure processing, wherein the playback device is coupled to a server processor via a network, the method further comprising

transferring the playback time limit to the playback device for secure processing;

and

using the secure processor to transfer at least a portion of the electronic presentation to the playback device for rendering, at least a portion of the rendering to take place in the non-secure processing.

13. The method of claim 12, wherein a secure processor is used to perform the secure processing, the method further comprising

using the secure processor to receive a secure time signal via the network;

and

using the secure time signal with the playback time limit to restrict playback of the electronic presentation by the playback device.

14. The method of claim 1, wherein the actual cumulative time does not include time during which the electronic presentation is not being played back.

15. The method of claim 14, wherein the playback device includes secure processing and non-secure processing, the method further comprising

using the non-secure processing to determine when one of the following modes of playback have been selected by a user:

pause, fast forward, rewind, stop, variable speed playback, variable speed rewind;

using the secure processing to update the actual cumulative time in response to one or more of the modes determined by the non-secure processing.

16. The method of claim 15, further comprising

omitting update of the actual cumulative time for the modes of pause, rewind, and stop.

17. The method of claim 16 further comprising

determining whether a mode is being used by monitoring the rate at which a requesting process makes requests for decryption.

18. The method of claim 16, further comprising

omitting update of the actual cumulative time for the mode of fast forward.

19. A method for limiting playback of an electronic presentation on a playback device, the method comprising

receiving a playback time limit;

measuring actual time of the electronic presentation at the playback device; and

comparing the actual playback time with the playback time limit to determine whether to permit additional playback of the electronic presentation.

20. The method of claim 19, wherein the step of comparing is performed in response to a request to decrypt a portion of the electronic presentation.

21. The method of claim 20, wherein the request to decrypt a portion of the electronic presentation is made to a secure processor.

22. The method of claim 19, wherein the playback time limit is provided in a content license transferred via a network to the playback device.

23. The method of claim 19, wherein the playback time limit is derived from a running time of the electronic presentation.

24. The method of claim 23, wherein the playback time limit is longer than the running time of the electronic presentation.

25. The method of claim 19, further comprising

receiving a “

number of plays”

limit, wherein the number of plays limit is used with the playback time limit to restrict playback of the electronic presentation by the playback device.

26. The method of claim 19, wherein the playback device includes a server that provides streamed content.

27. The method of claim 19, wherein the playback device includes both secure and non-secure processing, wherein the playback device is coupled to a network, the method further comprising

using the secure processing to receive the playback time limit;

and

using the non-secure processing to render at least a portion of the electronic presentation.

28. The method of claim 27, wherein a secure processor is used to perform the secure processing, the method further comprising

using the secure processor to receives a secure time signal via the network;

and

using the secure time signal with the playback time limit to restrict playback of the electronic presentation by the playback device.

29. The method of claim 19, wherein the actual cumulative time does not include time during which the electronic presentation is not being played back.

30. The method of claim 29, wherein the actual cumulative time does not include time during which the electronic presentation is in one or more of the following modes:

pause, rewind, or stop.

31. An apparatus for limiting playback of an electronic presentation on a playback device, the apparatus comprising

a receiver for receiving a playback time limit;

a detector for measuring actual time of the electronic presentation at the playback device; and

a comparator for comparing the actual playback time with the playback time limit to determine whether to permit additional playback of the electronic presentation.

32. A computer-readable medium including instructions executable by a processor for limiting playback of an electronic presentation in a digital rights management system, wherein a playback device is used to play back the electronic presentation, the computer-readable medium comprising

one or more instructions for transferring a playback time limit to the playback device, wherein the playback time limit is used to restrict playback of the electronic presentation according to a measure of actual cumulative time of the electronic presentation by the playback device.