JP2002542502A - Authentication and verification in digital camera architecture - Google Patents

Abstract

(57) Abstract Advanced digital cameras include non-volatile memory in which security values used to generate digital signatures for photographs are stored. A processor in the advanced digital camera hashes the digital data of the photo to process the photo and generate a hash digest. The processor then performs the digital signature function using the security value to generate a digital signature for the photograph.

Description

DETAILED DESCRIPTION OF THE INVENTION

TECHNICAL FIELD The present invention relates to digital cameras, and more particularly, to authentication and verification in digital camera architectures.

BACKGROUND As digital cameras have become a widely used consumer product, photographs taken with digital cameras may be increasingly used for applications such as insurance claims and law enforcement. There is. However, unlike previous photographic cameras, digital photography provides a new amateur photographer using a standard personal computer with a means to "tamper" or manipulate the photograph without being seen. This is because digital cameras allow you to manipulate, change, and edit photos without compromising the quality of the photos. Therefore, such an operation cannot be detected. This means that outlaws can use digital photos to scam insurance,
Or it would give the opportunity to tampering with the evidence used in court.

SUMMARY OF THE INVENTION In accordance with a preferred embodiment of the present invention, an enhanced digital camera includes a non-volatile memory in which security values used to generate a digital signature for a photograph are stored. Is stored. A processor in the enhanced digital camera processes the photo by hashing the digital data of the photo to generate a hash digest. The processor then performs a digital signature function on the hash digest using the security value to generate a digital signature for the photo.

In a preferred embodiment, the processor hashes the camera's serial number and date and time stamp along with the digital photo data to generate a hash digest. The security value is, for example, a specific private key that is part of a private / public key pair. To increase the security of the private key, the non-volatile memory and the processor are in a secure integrated circuit, and the processor generates a private / public key pair. The non-volatile memory is, for example, a one-time programmable memory.
The public key is stored, for example, in a third party's database and can be accessed (using the enhanced digital camera's serial number) when a photo taken with the enhanced digital camera needs to be authenticated. Can be.

[0005] The digital signature is stored together with the digital data of the photograph. To authenticate the photo, the digital data of the photo is hashed to generate a calculated hash digest. For example, the camera serial number and date / time stamp are hashed together with the digital photo data. A digital signature function is performed on the digital signature of the photo using the public key of the enhanced digital camera to generate the extracted hash digest. The calculated hash digest is compared to the extracted hash digest to determine if the photo has been authentically modified.

The authentication and integrity verification utilized in the enhanced digital camera architecture of the present invention provides the necessary functionality to authenticate photos and detect changes.

FIG. 1 is a simplified block diagram of the architecture of an enhanced digital camera 10 that enables the functionality required to prevent alteration of digital photographic data. Incorporates authentication and verification to The digital camera 10 can operate in, for example, an authentication and integrity verification (AIV) mode or a non-AIV mode. In the AIV mode, the architecture of the enhanced digital camera 10 authenticates and digitally signs each photo as each image is captured. As a result, it is possible to detect unauthorized changes to the original photo. The hash function is used to protect the integrity of the original digital image, and the digital signature function is used to protect the image from being authentic. The solution does not prevent tampering, but allows tampering detection.

[0008] Enhanced digital camera 10 includes standard functional blocks normally included in digital cameras. For example, the enhanced digital camera 10 includes an image processor 11 and a memory module for storing captured images.

The secure camera integrated circuit 12 includes other functional blocks of the enhanced digital camera 10. These functional blocks are included in a single integrated circuit, which not only reduces manufacturing costs, but also provides the necessary security level to ensure that private key components are never exposed outside the secure camera integrated circuit 12. provide.

The functional components included in the secure camera integrated circuit 12 include an analog-to-digital (A / D) converter block 21, a digital signal processing block 23, a random access memory (RAM) 24, and a read-only memory (ROM) 25. And a memory module interface 27.

In addition, secure camera integrated circuit 12 includes one-time programmable (OTP) memory 26. The one-time programmable memory 26 is a secure memory that stores the security value of the digital camera. One-time programmable (O
Instead of the TP) memory 26, the memory 26 may be a flash memory, a programmable read only memory (PROM), an EEPROM, or any other memory capable of permanently and securely storing the security value of the enhanced digital camera 10. Can be manufactured.

The security value of the enhanced digital camera 10 is, for example, a specific public / private key pair. Alternatively, the digital camera security value is any particular security value that can be used to generate a digital signature.

For example, the microprocessor 23 generates a public / private key pair when the enhanced digital camera 10 is manufactured. The microprocessor 23 generates the public /
Program the private key pair into the OTP memory. At that time, the components of the public key in the public / private key pair are sent from the secure camera integrated circuit 12 and the enhanced digital camera 10. At that time, for example, a secure third party (certification body) records the public key along with the serial number to authenticate and verify the integrity of the photo in the future. For example, the secure third party may be a company engaged in a business that issues digital certificates to individuals and corporations.

FIG. 2 illustrates an authentication and verification process utilized in the enhanced digital camera 10 according to a preferred embodiment of the present invention. When a picture is taken, the resulting digital data 31 is stored in RAM 24. The date and time stamp 41 generated by the real-time clock 32 is added before the digital data 31. Also, the camera serial number 42 of the enhanced digital camera 10 is
Is added before. To generate a hash digest 35, the digital data 31, date and time stamp 41 and camera serial number 42 are hashed together using a hash function 34. The digital signature function 37 digitally signs the hash digest 35 with a specific private key 36 to generate a digital signature 44. The specific private key 36 is used for the enhanced digital camera 1.
Private key used only for 0. The digital signature 44 is attached after the digital data 31. Date / time stamp 41, camera serial number 42,
The entire configuration of the photograph including the digital data 31 and the digital signature 44 is stored in the memory module 13.

[0015] The stored configuration of the photo allows the photo to be authenticated. In effect, when a picture is taken, a digital signature of the picture has been created.
This allows any changes to the video to be detected.

The preferred embodiment of the present invention withstands the attacks of people trying to bypass the protection system. The two most obvious ways of attacking the protection system are to modify the photo (digital data 31) and return it to the memory module 13, or to combine the photo (digital data 31) with the digital signature 44 and thus the two matches. Change and return the result to the memory module 13. However, both of these attacks can be defended using the preferred embodiment of the present invention.

FIG. 3 shows when the photo (digital data 31) is changed and returned to the memory module 13, or when both the photo (digital data 31) and the digital signature 44 are changed and returned to the memory module 13. , Illustrates the detection process used to detect.

A secure database 60 is used to store the public key of the enhanced digital camera. For example, database 60 is a third party database and is used to archive camera serial numbers and associated public keys. As shown in FIG. 3, each of the representative entries 61, 62, 63 and 64 includes a camera serial number and an associated public key.

A hash function 71 is used to hash digital data 53, date and time stamp 51, and camera serial number 52 together to detect whether digital data 53 in configuration 50 has changed. A hash digest 72 is generated. The camera serial number 52 is used to access a specific public key 73 of the enhanced digital camera from the database 60. The digital signature function 74 extracts the hash digest 75 extracted from the digital signature 50 using the specific public key 73. The comparison function 76
Comparing the calculated hash digest 72 with the extracted hash digest 75, the output 77 indicates whether there is a match (the photo is genuine and unaltered) or no match (the photo is genuine and changed) Is shown.

The detection process of FIG. 3 is based on the case where the photograph is changed and returned to the memory module,
It detects both the case where the photograph and the digital signature are changed and both are returned to the memory module 13. Changing the photo (but not the signature) and returning it to the memory module results in a mismatch between the hash value of the new image and the hash value stored in the signature. Also, changing both the photo and the signature will result in a mismatch between the calculated hash value and the hash value stored in the signature. Even if the hash value stored in the signature is properly calculated, if the hash value is not signed with the correct private key, it is detected as a changed photo. Thus, anyone attempting to sign a public / private key pair that is not registered in the photo will be detected.

While the present invention provides effective protection, there are possible ways in which one can attempt to bypass the protection system. For example, an attempt can be made to extract a private key from a camera registered with a physical attack. The private key extracted at that time can be used to sign the hash value of the modified photo. If you suspect this type of tampering, you should investigate the enhanced digital camera for signs of tampering to determine if a physical attack has taken place. Also, when designing a secure camera IC 12, measures can be taken to ensure that it is very difficult for an attacker to access the private key. The strength and integrity of the system is based on the ability to store data (ie, a private key) inside the camera in a secure manner. The most effective way to do this, as mentioned above,
The enhancement is to utilize a one-time programmable memory that is fully integrated into a single-chip architecture within a digital camera. In this way, there is no need to send private key information outside the secure integrated circuit, and the ability to protect the integrity of the picture is improved.

Another possible attack on the integrity of the system is for an attacker to access database 60 to insert a fake public key. If so, the photo is "authenticated" with a fake private key related to the fake public key. However, if a fake public key is inserted into a third-party database that has a security function, it will always be detected. Databases used to secure digital signatures are typically digitally signed by a third party, adding an extra layer of security. Providing similar protections in the database 60 will provide effective protection for embodiments of the present invention.

The above discussion merely discloses and describes exemplary methods and embodiments of the present invention. As will be appreciated by those skilled in the art, the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Accordingly, the disclosure of the present invention is intended to be illustrative, but not limiting, of the scope of the invention, which is set forth in the following claims.

[Brief description of the drawings]

FIG. 1 is a simplified block diagram of a digital camera architecture incorporating authentication and verification according to a preferred embodiment of the present invention.

FIG. 2 illustrates an authentication and verification process in a digital camera according to a preferred embodiment of the present invention.

FIG. 3 illustrates a detection process used to detect changes in digital images and / or digital signatures according to a preferred embodiment of the present invention.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 5/225 H04N 101: 00 // H04N 101: 00 H04L 9/00 675D (72) Inventor Mark, Leonard Gilbert, East, Betsy, Lane, 1027 BA02 CE08 CE09 CG07 CH01 DC31 5C022 AA13 AB68 AC42 AC69 5C076 AA14 AA16 BA06 5J104 AA08 AA09 LA05 LA06 NA12

Claims (20)

[Claims] 1. A method for protecting a photograph taken by a digital camera, comprising: (a) hashing digital data of the photograph to generate a hash digest; and (b) digitally processing the photograph for the photograph. Performing a digital signature function on the hash digest using a security value to generate a signature. 2. The method of claim 1, further comprising the step of: (c) storing the digital signature with digital data of the photograph. 3. The method of claim 1, wherein step (a) includes hashing a serial number of the camera with the digital data of the photograph to generate the hash digest. 4. The method of claim 1, wherein step (a) includes hashing the camera's serial number and date and time stamp with the digital data of the photograph to generate the hash digest. 5. The method of claim 1, wherein in step (b), the security value is a specific private key that is part of a private / public key pair. 6. The method of claim 1, wherein steps (a) and (b) are both performed in a secure integrated circuit. 7. A method for authenticating a photograph taken by a digital camera, comprising: (a) hashing digital data of the photograph to generate a calculated hash digest; and (b) the digital camera. (C) performing a digital signature function on the digital signature of the photo using the security value of the digital camera to generate an extracted hash digest; (D) comparing the calculated hash digest with the extracted hash digest to determine whether the photograph is authentic. 8. The method of claim 7, wherein in step (c), the digital signature is stored with digital data of the photograph. 9. The method of claim 7, wherein step (a) includes hashing a serial number of the camera with the digital data of the photograph to generate the calculated hash digest. 10. The method of claim 7, wherein step (a) includes hashing the camera's serial number and date and time stamp with the digital data of the photo to generate the calculated hash digest. . 11. The method of claim 7, wherein in step (b), the security value is a public key that is part of a private / public key pair. 12. An advanced digital camera comprising: a non-volatile memory in which security values used to generate a digital signature for a photo are stored; and a processor, wherein the processor transmits digital data of the photo. Processing the photo by hashing to generate a hash digest, and wherein the processor performs a digital signature function on the hash digest using the security value to generate a digital signature for the photo. Advanced digital camera to implement. 13. The advanced digital camera of claim 12, wherein said processor stores said digital signature with digital data of said photograph. 14. The processor of claim 12, wherein when the processor hashes the digital data of the photo, the processor hashes the serial number of the camera with the digital data of the photo to generate the hash digest. Advanced digital camera. 15. The processor of claim 14, wherein when the processor hashes the digital data of the photo, the processor hashes the serial number and date and time stamp of the camera with the digital data of the photo to generate the hash digest. 13. The advanced digital camera according to 12. 16. The advanced digital camera according to claim 12, wherein the security value is a specific private key that is part of a private / public key pair. 17. The advanced digital camera according to claim 12, wherein said non-volatile memory and said processor are in a secure integrated circuit. 18. The nonvolatile memory according to claim 12, wherein the nonvolatile memory is a one-time programmable memory.
An advanced digital camera according to item 1. 19. The advanced digital camera according to claim 12, wherein said processor generates said security value. 20. The advanced digital camera according to claim 12, wherein the security value is a specific private key that is part of a private / public key pair generated by the processor.