Display unit storing and using a cryptography key

• US 20040186991A1
• Filed: 03/29/2004
• Published: 09/23/2004
• Est. Priority Date: 02/25/2000
• Status: Active Grant

• Current Assignee: Tamiras Per Pte Ltd LLC (Intellectual Ventures LLC)
• Original Assignee: Genesis Microchip Corp (STMicroelectronics NV)
• Inventors: Noorbakhsh, Ali, Kobayashi, Osamu, Hang, Chia-Lun, Chan, Tzoyao, Soong, Jih-Hsien
• Granted Patent: US 7,206,943 B2
• Time in Patent Office: Days
• US Class Current: 713/153
• CPC Class Codes: G06F 21/84 output devices, e.g. displays or monitors
• CPC Class Codes: H04L 9/0897 involving additional devices, e.g. trusted platform module [TPM], smartcard or USB

Abstract

Keys (e.g., decryption key, authentication key) are stored in a non-volatile memory of a display unit. The keys are retrieved in encrypted form into an integrated circuit. The integrated circuit decrypts the keys and uses the keys. As the keys are available in decrypted form only within the integrated circuit and potentially only during use, the keys may not be available to unauthorized third parties.

Claims

1. A method of using a cryptographic key in a display device, comprising:

in a display device having a printed circuit board (PCB) and a master block, providing a key to the PCB by the master block;

selecting one of a number of encryption protocols available to the PCB;

encrypting the key based upon the selected encryption protocols;

storing the encrypted key in a non-volatile memory by the PCB;

decrypting the stored encrypted key, as needed, by the PCB based upon the selected encryption protocol.

2. The method as recited in claim 1, wherein the key is one of a plurality of keys and further comprising:

providing a number of the plurality of keys.

3. The method as recited in claim 2, further comprising:

selecting one of the number of available encryption protocols for each of the provided keys; and

encrypting each of the provided keys based upon a particular one of the selected encryption protocols.

4. The method as recited in claim 3, further comprising:

storing the encrypted keys in the non-volatile memory.

5. The method as recited in claim 4, further comprising:

decrypting selected ones of the stored encrypted keys, as needed.

6. The method as recited in claim 2, wherein the plurality of keys includes a decryption key and an authentication key.

7. The method as recited in claim 6, further comprising:

receiving a cryptography related command.

8. The method as recited in claim 7 wherein the cryptograhy command includes an authentication request and a number of associated authentication request parameters.

9. The method as recited in claim 8, wherein the authentication request is an HDCP authentication request.

10. The method as recited in claim 8, further comprising:

retrieving an encrypted authentication key from the non volatile memory corresponding to the authentication request; and

decrypting the authentication request based upon a corresponding decryption protocol.

11. The method as recited in claim 10, further comprising:

responding to the authentication request based on the decrypted authentication request.

12. Computer program product for using a cryptographic key in a display device, comprising:

in a display device having a printed circuit board (PCB) and a master block, computer code for providing a key to the PCB by the master block;

computer code for selecting one of a number of encryption protocols available to the PCB;

computer code for encrypting the key based upon the selected encryption protocols;

computer code for storing the encrypted key in a non-volatile memory by the PCB;

computer code for decrypting the stored encrypted key, as needed, by the PCB based upon the selected encryption protocol; and

computer readable medium for storing the computer code.

13. Computer program product as recited in claim 12, wherein the key is one of a plurality of keys and further comprising:

computer code for providing a number of the plurality of keys.

14. Computer program product as recited in claim 13, further comprising:

computer code for selecting one of the number of available encryption protocols for each of the provided keys; and

computer code for encrypting each of the provided keys based upon a particular one of the selected encryption protocols.

15. Computer program product as recited in claim 14, further comprising:

computer code for storing the encrypted keys in the non-volatile memory.

16. Computer program product as recited in claim 15, further comprising:

computer code for decrypting selected ones of the stored encrypted keys, as needed.

17. Computer program product as recited in claim 13, wherein the plurality of keys includes a decryption key and an authentication key.

18. Computer program product as recited in claim 17, further comprising:

computer code for receiving a cryptography related command.

19. Computer program product as recited in claim 18 wherein the cryptograhy command includes an authentication request and a number of associated authentication request parameters.

20. Computer program product as recited in claim 19, wherein the authentication request is an HDCP authentication request.

21. Computer program product as recited in claim 19, further comprising:

computer code for retrieving an encrypted authentication key from the non volatile memory corresponding to the authentication request; and

computer code for decrypting the authentication request based upon a corresponding decryption protocol.

22. Computer program product as recited in claim 21, further comprising:

computer code for responding to the authentication request based on the decrypted authentication request.