Semiconductor imaging sensor with on-chip encryption

• US 6,400,824 B1
• Filed: 11/12/1997
• Issued: 06/04/2002
• Est. Priority Date: 11/12/1996
• Status: Expired due to Term

• Current Assignee: California Institute of Technology
• Original Assignee: California Institute of Technology
• Inventors: Fossum, Eric R., Mansoorian, Barmak
• Primary Examiner(s): Barrón, Jr., Gilberto
• Assistant Examiner(s): SONG, HOSUK
• Application Number:
  US08/968,027
• Time in Patent Office: 1,665 Days
• Field of Search: 380/10, 380/29, 380/52, 380/269, 380/200, 380/217, 358/405, 345/157, 250/208, 713/176, 713/194, 713/189, 713/193, 257/292, 348/294
• US Class Current: 380/269
• CPC Class Codes: H04N 19/00 Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
• CPC Class Codes: H04N 21/2187 Live feed
• CPC Class Codes: H04N 21/2347 involving video stream encryption
• CPC Class Codes: H04N 21/4223 Cameras H04N23/00 takes precedence
• CPC Class Codes: H04N 25/00 Circuitry of solid-state image sensors [SSIS]; Control thereof
• CPC Class Codes: H04N 7/1675 Providing digital key or authorisation information for generation or regeneration of the scrambling sequence pseudo-random number generators in general G06F7/58

Abstract

An imaging device integrating a photosensing array, at least one analog-to-digital converter, and an encryption circuit on a single substrate. An optical image can be directly converted into encrypted digital data prior to transmission the image off the chip.

Claims

1. A semiconductor imaging device, comprising:

a substrate formed of a semiconductor material;

a plurality of CMOS image sensing elements, formed on said substrate to construct an imaging array which is responsive to an optical image to produce an analog electrical representation of said optical image;

at least one analog-to-digital converter formed on said substrate and electrically connected to said imaging array, operating to convert said analog electrical representation into a digital image; and

an encryption circuit formed on said substrate and configured to encrypt said digital image according to an encryption key.

2. The device as in claim 1, wherein each of said sensing elements includes one of a photogate, a phototransistor, or a photodiode.

3. The device as in claim 1, wherein each of said sensing elements includes an active pixel sensor.

4. The device as in claim 1, wherein said encryption circuit is configured to perform DES encryption.

5. The device as in claim 1, wherein said encryption circuit is configured to perform RSA encryption.

6. A semiconductor imaging device, comprising:

a substrate formed of a semiconductor material;

a plurality of image sensing elements, formed on said substrate to construct an imaging array which is responsive to an optical image to produce an analog electrical representation of said optical image;

at least one analog-to-digital converter formed on said substrate and electrically connected to said imaging array, operating to convert said analog electrical representation into a digital image;

a marking circuit formed on said substrate and configured to produce a unique digital code, wherein said encryption circuit is operable to superimpose said digital code onto said digital image;

an encryption circuit formed on said substrate and configured to encrypt said digital image according to an encryption key and to encrypt both said digital code and said digital image as an encrypted stream.

7. A semiconductor imaging device, comprising:

a substrate formed of a semiconductor material;

a plurality of image sensing elements, formed on said substrate to construct an imaging array which is responsive to an optical image to produce an analog electrical representation of said optical image;

at least one analog-to-digital converter formed on said substrate and electrically connected to said imaging array, operating to convert said analog electrical representation into a digital image;

an encryption circuit formed on said substrate and configured to encrypt said digital image according to an encryption key and to encrypt said digital image as an encrypted stream; and

a digital data compression circuit formed on said substrate and electrically connected between said analog-to-digital converter and said encryption circuit, said digital data compression circuit operating to compress a size of said digital image prior to application to said encryption circuit.

8. The device as in claim 7, further comprising a microprocessor formed on said substrate and configured to perform at least part of said encryption of said compressed representation of said digital image.

9. The device as in claim 8, further comprising a memory circuit formed on said substrate and configured to store information for said microprocessor.

10. A semiconductor imaging device, comprising:

an imaging sensing array having a plurality of CMOS sensing elements formed on a substrate and operating to respond to an optical image to produce an analog electrical representation of said optical image;

an analog-to-digital conversion module formed on said substrate and electrically connected to said imaging array, operating to convert said analog electrical representation into a digital image; and

an encryption circuit formed on said substrate and configured to encrypt said digital image according to an encryption key.

11. The device as in claim 10, wherein each of said sensing elements includes a CMOS active pixel sensor.

12. The device as in claim 10, wherein said analog-to-digital conversion module includes a single analog-to-digital converter which sequentially converts analog signals from said sensing elements into digital signals.

13. The device as in claim 10, wherein said analog-to-digital conversion module includes a plurality of analog-to-digital converters which a re electrically connected in parallel to one another and simultaneously process analog signals from said sensing elements into digital signals.

14. The device as in claim 10, further comprising a microprocessor formed on said substrate and configured to perform part of said encryption of said digital image.

15. The device as in claim 14, further comprising a memory circuit formed on said substrate and configured to store information for said microprocessor.

16. The device as in claim 10, wherein said encryption circuit is configured to perform the DES encryption and comprises:

an input register receiving digital data of said digital image from said analog-to-digital conversion module;

a logic gate connected to said input register to perform an XOR operation on said digital data according to a feedback digital signal to said logic gate;

a DES processing circuit having an input connected to said logic gate and operating to perform the DES encryption based on said encryption key on said digital data from said logic gate to produce an encrypted output at an output; and

a feedback loop interconnecting said output of said DES processing circuit and said logic gate and operating to provide said feedback digital signal.

17. The device as in claim 16, wherein said feedback loop in said encryption circuit further comprises a memory circuit and a digital signal multiplexing circuit that are operable to superimpose a pseudo random number onto a first block of data in said digital image to produce a unique seed for said DES encryption for said optical image.

18. A method for performing image encryption, comprising:

capturing an optical image by using an imaging device having an image sensing array formed on a substrate to produce an analog electronic representation of said optical image;

converting said analog representation into a digital image by using an on-chip analog-to-digital conversion circuit formed on said substrate; and

using an on-chip encryption circuit formed on said substrate to encrypt said digital image based on an encryption algorithm so that said imaging device directly sends out an encrypted digital image.

19. The method as in claim 18, wherein said encryption circuit is configured to perform the DES or RSA encryption.

20. The method as in claim 18, further comprising a step of forming a digital signature associated with said digital image by using a unique digital code which is unique to each different chip, and is generated by a circuit formed on said substrate.

21. A method as in claim 18, further comprising, prior to said using, compressing said digital image to form a compressed version of said digital image, and wherein said encryption circuit encrypts said compressed digital image.

22. An encrypted imaging chip, comprising:

a single continuous substrate of silicon;

a CMOS image sensor, formed in said single substrate of silicon;

a digital signal signature production element, which produces a digital signature which is unique to said single substrate of silicon, and which will be different for other substrates of silicon, and which is encrypted and such that a receiver of an image who has an authorized decryption code can determine a source of said image, and such that a receiver without said decryption code cannot determine said source of said image and

an image compression element on said chip, and compressing said image prior to encryption.

23. A device as in claim 22, wherein said image sensor is an active pixel sensor.

24. A method of transmitting an image from a first location to a second location, comprising:

forming a semiconductor substrate which includes a unique substrate ID, an image sensor, and an on-chip encryption element, all on said semiconductor substrate;

acquiring an image on said substrate, and associating said image, on said substrate, with said unique substrate ID;

encrypting both said image and said unique substrate ID into an encrypted stream;

sending said encrypted stream to said second location; and

at said second location, using a decryption key to decrypt said encrypted stream to determine a source of said encrypted stream from said unique substrate ID.

25. A semiconductor imaging device, comprising:

a substrate formed of a semiconductor material;

a plurality of CMOS image sensing elements, formed on said substrate, to construct an imaging array which is responsive to an optical image, to produce an analog electrical representation of said optical image;

at least one analog-to-digital converter, formed on said substrate, and electrically connected to said imaging array, operating to convert said analog electrical representation into a digital image;

a digital signal signature production element, which produces a digital signature which is unique to said single substrate of silicon, and which will be different for other substrates of silicon;

an encryption circuit formed on said substrate and configured to encrypt said digital image and digital signal signature production element, according to an encryption key and which is encrypted and such that a receiver of an image who has an authorized decryption code can determine a-source of said image from said encrypted digital signature, and such that a receiver without said decryption code cannot determine said source of said image from said encrypted digital signature; and

a digital data compression circuit formed on said substrate and electrically connected between said analog-to-digital converter and said encryption circuit, said digital data compression circuit operating to compress a size of said digital image prior to application to said encryption circuit.