Display unit storing and using a cryptography key

• US 6,845,450 B1
• Filed: 08/31/2000
• Issued: 01/18/2005
• Est. Priority Date: 02/25/2000
• Status: Active Grant

• Current Assignee: Tamiras Per Pte Ltd LLC (Intellectual Ventures LLC)
• Original Assignee: Genesis Microchip Inc. (STMicroelectronics NV)
• Inventors: Noorbakhsh, Ali, Kobayashi, Osamu, Hang, Chia-Lun, Chan, Tzoyao, Soong, Jih-Hsien
• Primary Examiner(s): Sheikh, Ayaz
• Assistant Examiner(s): SHERKAT, AREZOO
• Application Number:
  US09/652,415
• Time in Patent Office: 1,601 Days
• Field of Search: 713/200, 713/201, 713/193, 380/201, 380/277, 380/228, 345/3.2, 711/163
• US Class Current: 726/5
• 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 display circuit for use in a display unit, said display circuit comprising:

a non-volatile memory storing a encrypted key, wherein said encrypted key is generated from an unencrypted key according to an encryption protocol; and

an integrated circuit coupled to said non-volatile memory, said integrated circuit receiving said key in encrypted form and decrypting said key to generate a decrypted key, said integrated circuit using said decrypted key wherein said integrated circuit comprises a key encryption circuit receiving said unencrypted key, said key encryption circuit generating said encrypted key form said unencrypted key according to said encryption protocol, a key decryption circuit receiving said encrypted key and generating said decrypted key according to said encryption protocol, a receiver adapted for receiving a plurality of digital data elements encoded in a display signal, wherein said digital data elements represent a plurality of pixel data elements in an encrypted form, said plurality of pixel data elements representing an image, and a data decryption circuit receiving said plurality of digital data elements and generating said plurality of pixel data elements, wherein said image is generated on a display screen based on said plurality of pixel data elements, and wherein said display signal is received according to TMDS format.

2. The display circuit as recited in claim 1 wherein said unencrypted key comprises an authentication key and said using comprise authenticating a source of data.

3. The display circuit as recited in claim 1 wherein said unencrypted key comprises a decryption key and said using comprise decrypting data.

4. The display circuit as recited in claim 1, wherein said display unit comprises an analog display unit 7.

5. The display circuit as recited in claim 1, wherein said display unit comprises a digital display unit.

6. The display circuit as recited in claim 1, wherein when a source of data is authenticated, said authenticating is performed using said unencrypted key based on data sent and received on a path connected to said display unit.

7. The display circuit as recited in claim 6, wherein said path is implemented using I²C protocol.

8. The display circuit as recited in claim 1, further comprising a master block external to said display unit that sends said unencrypted key-wherein when said encrypted key is sent to said master block, said master block stores said encrypted key in said non-volatile memory.

9. A integrated circuit, comprising:

a key encryption circuit adapted to receive an unencrypted key and generating an encrypted key from said unencrypted key according to an encryption protocol;

a key decryption circuit adapted to receive said encrypted key generate said decrypted key according to said encryption protocol;

a receiver adapted to receive a plurality of digital data elements encoded in a display signal that is received according to TMDS format and that represents a plurality of pixel data elements in an encrypted form, wherein said plurality of pixel data elements represents an image that is generated on a display screen based on said plurality of pixel data element; and

a data decryption circuit adapted to receive said plurality of digital data elements and generate said plurality of pixel data elements.

10. The integrated circuit as recited in claim 9 wherein the integrated circuit is

coupled to a non-volatile memory suitable for storing the encrypted key.

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

a memory adapted to receive said encrypted key;

a port coupled to said memory, said port receiving said encrypted key from said memory and sending said encrypted key to a master block adapted to store said encrypted key in said non-volatile memory.

12. The integrated circuit as recited in claim 9, wherein the integrated circuit is coupled to a display unit.

13. The integrated circuit as recited in claim 12, where said display unit is a digital display unit.

14. The integrated circuit as recited in claim 12, wherein said display unit is an analog display unit.

15. The method as recited in claim 14, further comprising:

storing an encrypted key generated from an unencrypted key according to an encryption protocol in a non-volatile memory.

16. A method of using and storing a cryptography key, comprising:

receiving an unencrypted key

generating said encrypted key from said unencrypted key according to an encryption protocol

generating a decrypted key by decrypting the encrypted key according to said encryption protocol;

receiving a plurality of digital data elements encoded in a display signal wherein said display signal is received according to TMDS format and wherein said digital data elements represent a plurality of pixel data elements in an encrypted form that represent an image;

decrypting said encrypted plurality of digital data elements;

generating said plurality of pixel data elements based upon said decrypted plurality of digital data elements; and

generating said image on a display screen based on said decrypted plural of pixel data elements.

17. Computer program product for using and storing a cryptography key comprising:

computer code for receiving an unencrypted key

computer code for generating said encrypted key from said unencrypted key according to an encryption protocol

computer code for generating a decrypted key by decrypting the encrypted key according to said encryption protocol;

computer code for receiving a plurality of digital data elements encoded in a display signal wherein said display is received according to TMDS format, and wherein said digital data elements represent a plurality of pixel data elements in an encrypted form that represent an image;

computer code for decrypting said encrypted plurality of digital data elements;

computer code for generating said plurality of pixel data elements based upon said decrypted plurality of digital data elements;

computer code for generating said image on a display screen based on said decrypted plurality of pixel data elements; and

computer readable medium for storing the computer code.