Digital camera with apparatus for authentication of images produced from an image file

• US 5,499,294 A
• Filed: 05/24/1995
• Issued: 03/12/1996
• Est. Priority Date: 11/24/1993
• Status: Expired due to Fees

• Current Assignee: Department of Health and Human Services (State of Victoria)
• Original Assignee: United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration
• Inventors: Friedman, Gary L.
• Primary Examiner(s): Buczinski, Stephen C.
• Application Number:
  US08/449,472
• Time in Patent Office: 293 Days
• Field of Search: 380/10, 380/30, 348/207, 348/441, 348/460, 348/469, 348/552
• US Class Current: 713/179
• CPC Class Codes: G07D 7/0034 using watermarks
• CPC Class Codes: G07D 7/004 using digital security elements, e.g. information coded on a magnetic thread or strip
• CPC Class Codes: H04L 2209/603 Digital right managament [DRM]
• CPC Class Codes: H04L 9/3236 using cryptographic hash functions
• CPC Class Codes: H04L 9/3247 involving digital signatures
• CPC Class Codes: H04N 1/32128 attached to the image data, e.g. file header, transmitted message header, information on the same page or in the same computer file as the image for information embedded in the image H04N1/32144
• CPC Class Codes: H04N 2005/91342 the copy protection signal being an authentication signal
• CPC Class Codes: H04N 2201/3233 of authentication information, e.g. digital signature, watermark
• CPC Class Codes: H04N 2201/3274 Storage or retrieval of prestored additional information
• CPC Class Codes: H04N 23/60 Control of cameras or camera modules
• CPC Class Codes: H04N 5/913 for scrambling ; for copy protection
• 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

A digital camera equipped with a processor for authentication of images produced from an image file taken by the digital camera is provided. The digital camera processor has embedded therein a private key unique to it, and the camera housing has a public key that is so uniquely related to the private key that digital data encrypted with the private key may be decrypted using the public key. The digital camera processor comprises means for calculating a hash of the image file using a predetermined algorithm, and second means for encrypting the image hash with the private key, thereby producing a digital signature. The image file and the digital signature are stored in suitable recording means so they will be available together. Apparatus for authenticating the image file as being free of any alteration uses the public key for decrypting the digital signature, thereby deriving a secure image hash identical to the image hash produced by the digital camera and used to produce the digital signature. The authenticating apparatus calculates from the image file an image hash using the same algorithm as before. By comparing this last image hash with the secure image hash, authenticity of the image file is determined if they match. Other techniques to address time-honored methods of deception, such as attaching false captions or inducing forced perspectives, are included.

Claims

1. A digital camera with apparatus for authentication of images produced from an image file taken by said digital camera of a scene, said digital camera having embedded therein a private key unique to said digital camera and a known public key so uniquely based upon said private key that digital data encrypted with said private key may be decrypted using said public key, said digital camera apparatus comprising

first means for calculating image hash of said image file using a predetermined algorithm,

second means for encrypting said image hash with said embedded private key, thereby producing a digital signature uniquely associated with said image file, and

third means for maintaining association of both said image file and said digital signature derived from said image file by said first and second means.

2. A combination as defined in claim 1 including separate apparatus for authenticating at any time said image file as being free of any alteration using said associated digital signature, said separate apparatus comprising

fourth means for decrypting said digital signature, using said public key, thereby deriving a secure image hash identical to said image hash produced by said first means of said digital camera apparatus by calculating image hash of said image file from said digital camera,

fifth means for calculating image hash of said image file that has been maintained in association with said digital signature, said fifth means using said predetermined algorithm, and

sixth means for comparing said image hash of said image file calculated by said fifth means with said secure image hash from said fourth means to determine authenticity of said image file that has been maintained in association with said digital signature for use of said image file in reproducing an image represented by said image file if both said image file and said secure image file match identically.

3. A combination as defined in claim 1 wherein said private key is embedded in said second means.

4. A combination as defined in claim 3 wherein said public key is published.

5. A combination as defined in claim 4 wherein said public key is published on said digital camera.

6. A combination as defined in claim 4 wherein said public key is digitally recorded in a border of said image file and is processed through hashing and encryption with said image file.

7. A combination as defined in claim 6 wherein further information is digitally recorded in said border regarding parameters of said digital camera extant at the time said image file is taken and is processed through hashing and encryption with said image file to assist in reproduction and interpretation of a reproduced image of said scene.

8. A combination as defined in claim 1 wherein focusing distance is digitally recorded in a border of said image file and is processed through hashing and encryption with said image file.

9. A combination as defined in claim 1 wherein range from said digital camera to one or more prominent objects in said scene are recorded in a border of said image file and is processed through hashing and encryption with said image file.