Methods and systems for effecting transmitter and receiver synchronization between a transmitter and a receiver of a transmitter/receiver network

• US 20050198528A1
• Filed: 10/22/2004
• Published: 09/08/2005
• Est. Priority Date: 03/04/2004
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.), Sony Electronics Inc. (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.), Sony Electronics Inc. (Sony Group Corp.)
• Inventors: Unger, Robert A.
• Granted Patent: US 8,527,755 B2
• Time in Patent Office: Days
• US Class Current: 726/22
• CPC Class Codes: H04L 2209/60 Digital content management, e.g. content distribution
• CPC Class Codes: H04L 9/0891 Revocation or update of secret information, e.g. encryption key update or rekeying

Abstract

Methods for effecting transmitter and receiver synchronization are disclosed. A method includes reading an authentication key value that is calculated by a receiver that is to receive protected content from a transmitter, determining if there has been a change in the authentication key value calculated by the receiver since it was last read and determining if a counter associated with the transmitter has a zero value. A re-authentication of the receiver is initiated if the counter associated with the transmitter has a non zero value and the authentication key value that is calculated from the receiver has changed.

Claims

1. A method for effecting transmitter and receiver synchronization, said method comprising:

reading an authentication key value that is calculated by a receiver that is to receive protected content from a transmitter;

determining if there has been a change in said authentication key value calculated by said receiver since it was last read;

determining if a counter associated with said transmitter has a zero value;

initiating a re-authentication of said receiver if said counter associated with said transmitter has a non zero value and a change in said authentication key value was coincidentally detected.

2. The method of claim 1 wherein said reading is performed by a controller.

3. The method of claim 1 wherein said key value comprises a value calculated based on a pseudo random number and a set of key selection values.

4. The method of claim 1 wherein said determining if there has been a change in said authentication key value comprises sensing each time the authentication key value is updated.

5. The method of claim 1 wherein said counter associated with said transmitter is configured to track a counter associated with said receiver.

6. The method of claim 5 wherein said non zero value indicates a counter mismatch between said counter associated with said transmitter and said counter associated with said receiver.

7. The method of claim 1 wherein said counter associated with said transmitter is a modulo 128 frame counter and wherein further said controller is an HDCP controller.

8. A system for effecting transmitter and receiver synchronization, said system comprising:

an authentication key value reader for reading an authentication key value that is calculated by a receiver that is to receive protected content from a transmitter;

an authentication key value change detector for determining if there has been a change in said authentication key value calculated by said receiver since it was last read;

a count determiner for determining if a counter of said transmitter has a zero value; and

an authentication initiator for initiating a re-authentication if said counter of said transmitter has a non zero value and said key value calculated by said receiver has coincidentally changed.

9. The system of claim 8 wherein said authentication key value reader comprises components of a controller.

10. The system of claim 8 wherein said authentication key value is calculated based on a pseudo random number and a set of key selection values.

11. The system of claim 8 wherein said counter associated with said transmitter is configured to track a counter associated with said receiver.

12. The system of claim 11 wherein if said count determiner detects a non zero value it indicates a counter mismatch between said counter associated with said transmitter and said counter associated with said receiver.

13. The system of claim 8 wherein said counter associated with said transmitter is a modulo 128 frame counter.

14. A method for effecting transmitter and receiver synchronization, said method comprising:

determining if a counter associated with a transmitter that transmits protected content to a receiver has a zero value;

reading an authentication key value calculated by said transmitter and reading an authentication key value that is calculated by said receiver if said counter associated with said transmitter has a zero value;

determining if said authentication key value that is calculated by said transmitter and said authentication key value that is calculated by said receiver match; and

initiating a re-authentication of said receiver if said authentication key value that is calculated by said transmitter and said authentication key value that is calculated by said receiver do not match and coincidentally said counter associated with said transmitter has a zero value.

15. The method of claim 14 wherein said reading is performed by a controller.

16. The method of claim 14 wherein said authentication value calculated by said receiver is calculated based on a pseudo random number and a set of key selection values.

17. The method of claim 15 wherein said determining if said authentication key value that is calculated by said transmitter and said authentication key value that is calculated by said receiver match comprises comparing said authentication key value that is calculated by said transmitter and said authentication key value that is calculated by said receiver each time said counter associated with said transmitter registers a zero value.

18. The method of claim 14 wherein said counter associated with said transmitter is a modulo 128 frame counter.

19. A system for effecting transmitter and receiver synchronization, said method comprising:

a count determiner for determining if a counter associated with a transmitter that transmits protected content to a receiver has a zero value;

an authentication key value reader for reading an authentication key value calculated by said transmitter and reading an authentication key value that is calculated by said receiver if said counter associated with said transmitter has a zero value;

an authentication key value match determiner for determining if said authentication key value that is calculated by said transmitter and said authentication key value that is calculated by said receiver match;

an authentication initiator for initiating a re-authentication of said receiver if said authentication key value that is calculated by said transmitter and said authentication key value that is calculated by said receiver do not match and said counter associated with said transmitter has a zero value.

20. The system of claim 19 wherein said authentication key value reader comprises components of a controller.

21. The system of claim 19 wherein said authentication key value transmitted from said receiver is calculated based on a pseudo random number and a set of key selection values.

22. The system of claim 19 wherein said counter associated with said transmitter is a modulo 128 frame counter.