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

• US 8,527,755 B2
• Filed: 10/22/2004
• Issued: 09/03/2013
• Est. Priority Date: 03/04/2004
• Status: Expired due to Fees

• 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.
• Primary Examiner(s): Flynn, Nathan
• Assistant Examiner(s): Su, Sarah
• Application Number:
  US10/970,869
• Publication Number:
  US 20050198528A1
• Time in Patent Office: 3,238 Days
• Field of Search: 713/155, 713/168, 713/181, 380/262, 380/229, 705/67
• US Class Current: 713/168
• 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 said receiver that is to receive protected content from said transmitter;

determining if there has been a change in said authentication key value that is 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, wherein said non zero value indicates a counter mismatch between said counter associated with said transmitter and a counter associated with said receiver when a change in said authentication key value is 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 1 wherein said counter associated with said transmitter is a modulo 128 frame counter and wherein further said controller is an HDCP controller.

7. 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 said receiver that is to receive protected content from said 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, wherein said non zero value indicates a counter mismatch between said counter associated with said transmitter and a counter associated with said receiver when a change in said authentication key value is coincidentally detected.

8. The system of claim 7 wherein said authentication key value reader comprises components of a controller.

9. The system of claim 7 wherein said authentication key value is calculated based on a pseudo random number and a set of key selection values.

10. The system of claim 7 wherein said counter associated with said transmitter is configured to track a counter associated with said receiver.

11. The system of claim 7 wherein said counter associated with said transmitter is a modulo 128 frame counter.