Authenticating images from digital cameras

• US 6,269,446 B1
• Filed: 06/26/1998
• Issued: 07/31/2001
• Est. Priority Date: 06/26/1998
• Status: Expired due to Term

• Current Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Original Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Inventors: Schumacher, Thomas, Kohler, Timothy L.
• Primary Examiner(s): Swann, Tod
• Assistant Examiner(s): Darrow, Justin T.
• Application Number:
  US09/105,046
• Time in Patent Office: 1,131 Days
• Field of Search: 713/160, 713/161, 713/162, 713/176, 713/177, 713/178, 713/179, 713/181, 380/30, 380/179, 380/234, 380/279
• US Class Current: 713/176
• CPC Class Codes: H04L 2209/60 Digital content management, e.g. content distribution
• CPC Class Codes: H04L 2209/80 Wireless network architectures or network communication protocols for wireless network security H04W12/00
• 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 2101/00 Still video cameras
• CPC Class Codes: H04N 2201/3214 of a date
• CPC Class Codes: H04N 2201/3215 of a time or duration
• CPC Class Codes: H04N 2201/3236 Details of authentication information generation
• CPC Class Codes: H04N 2201/3253 Position information, e.g. geographical position at time of capture, GPS data
• CPC Class Codes: H04N 2201/3274 Storage or retrieval of prestored additional information
• CPC Class Codes: H04N 2201/3277 The additional information being stored in the same storage device as the image data

Abstract

Authentication of image from digital cameras with GPS-derived time and location data is disclosed. With the wide-spread availability of today'"'"'s desktop tools and imaging devices, unethical manipulation of digital image data is common, such that digital images are not ordinarily reliable and can be subject to trickery and forgery. In the past, imagery such as photographs and digital images were reliable enough to serve as documentary evidence in most cases, since a skilled craftsman was needed to modify the images and commit fraud. However, skilled craftsmen are no longer needed, and digital images can be modified by even a casual user. Moreover, time data and location data are not ordinarily included in digital images. According to the invention, a digital camera system documents the time, date and location where a digital image was taken, using GPS-derived data from a secure connection. The validity and authenticity of the digital image, as well as the time data and location data, is then protected with a public key signature system that provides a digital signature by which the image and time and location information can be authenticated.

Claims

1. A method for forming a digital signature for authentication of image data for a digital camera that has captured event data for the image data, comprising the steps of:

creating a message digest for the image data, the message digest being derived from the image data and from the event data;

encrypting the message digest with a private key unique to and secured with the digital camera; and

creating an image file for the image data, the image file having a header that includes the private-key-encrypted message digest together with unencrypted event data.

2. A method according to claim 1, wherein the event data comprises GPS-derived data.

3. A method according to claim 1, wherein the event data includes time stamp data and location data.

4. A method according to claim 3, wherein said step of creating the message digest includes creating the message digest with digital camera information data.

5. A method according to claim 3, wherein said header includes unencrypted camera information data.

6. A method according to claim 1, wherein said header includes a public key complementary to the private key and which can be used to decrypt the encrypted message digest.

7. A method according to claim 1, wherein said step of creating a message digest includes the step of using a hashing function which through pre-arrangement can be used to validate authenticity based on unencrypted data in the header.

8. A method according to claim 7, wherein said header includes an identifier for the hashing function.

9. An apparatus for forming a digital signature for authentication of image data for a digital camera that has captured event data for the image data, said apparatus comprising:

a first creation means for creating a message digest for the image data, the message digest being derived from the image data and from the event data;

means for encrypting the message digest with a private key unique to and secured with the digital camera; and

a second creation means for creating an image file for the image data, the image file having a header that includes the private-key-encrypted message digest together with unencrypted event data.

10. An apparatus according to claim 9, wherein the event data comprises GPS-derived data.

11. An apparatus according to claim 9, wherein the event data includes time stamp data and location data.

12. An apparatus according to claim 11, wherein said first creation means includes means for creating the message digest with digital camera information data.

13. An apparatus according to claim 11, wherein said header includes unencrypted camera information data.

14. An apparatus according to claim 9, wherein said header includes a public key complementary to the private key and which can be used to decrypt the encrypted message digest.

15. An apparatus according to claim 9, wherein said first creation means includes a hashing function which through pre-arrangement can be used to validate authenticity based on unencrypted data in the header.

16. An apparatus according to claim 15, wherein said header includes an identifier for the hashing function.

17. An apparatus for forming a digital signature for authentication of image data for a digital camera that has captured event data for the image data, comprising:

a program memory for storing process steps of;

(1) creating a message digest for the image data, the message digest being derived from the image data and from the event data, (2) encrypting the message digest with a private key unique to and secured with the digital camera, and (3) creating an image file for the image data, the image file having a header that includes the private-key-encrypted message digest together with unencrypted event data; and

a processor for executing the process steps stored in said memory.

18. An apparatus according to claim 17, wherein the event data comprises GPS-derived data.

19. An apparatus according to claim 17, wherein the event data includes time stamp data and location data.

20. An apparatus according to claim 19, wherein said step of creating the message digest includes creating the message digest with digital camera information data.

21. An apparatus according to claim 19, wherein said header includes unencrypted camera information data.

22. An apparatus according to claim 17, wherein said header includes a public key complementary to the private key and which can be used to decrypt the encrypted message digest.

23. An apparatus according to claim 17, wherein said step of creating a message digest includes the step of using a hashing function which through pre-arrangement can be used to validate authenticity based on unencrypted data in the header.

24. An apparatus according to claim 23, wherein said header includes an identifier for the hashing function.

25. Computer-executable process steps stored on a computer readable medium, said computer-executable process steps for forming a digital signature for authentication of image data for a digital camera that has captured event data for the image data, said computer-executable process steps comprising:

a first creating step to create a message digest for the image data, the message digest being derived from the image data and from the event data;

an encrypting step to encrypt the message digest with a private key unique to and secured with the digital camera; and

a second creating step to create an image file for the image data, the image file having a header that includes the private-key-encrypted message digest together with unencrypted event data.

26. Computer-executable process steps according to claim 25, wherein the event data comprises GPS-derived data.

27. Computer-executable process steps according to claim 25, wherein the event data includes time stamp data and location data.

28. Computer-executable process steps according to claim 27, wherein said first creating step to create a message digest includes a creating step to create the message digest with digital camera information data.

29. Computer-executable process steps according to claim 27, wherein said header includes unencrypted camera information data.

30. Computer-executable process steps according to claim 25, wherein said header includes a public key complementary to the private key and which can be used to decrypt the encrypted message digest.

31. Computer-executable process steps according to claim 25, wherein said first step of creating to create a message digest includes a using step to use a hashing function which through pre-arrangement can be used to validate authenticity based on unencrypted data in the header.

32. Computer-executable process steps according to claim 31, wherein said header includes an identifier for the hashing function.

33. A method for validating authenticity of an image file containing image data and a header that includes a private-key-encrypted message digest together with unencrypted data including event data that went into forming the message digest, said method comprising the steps of:

obtaining a public key complementary to a private key used to encrypt the message digest;

decrypting the private-key-encrypted message digest using the public key so as to obtain a message digest;

calculating a trial message digest using a hashing function the same as the hashing function used to form the private-key-encrypted message digest, and also using the unencrypted event data in the header; and

comparing the trial message digest to the decrypted message digest to determine the authenticity of the image file,

wherein the event data includes location data.

34. A method according to claim 33, wherein the location data comprises GPS-derived data.

35. A method according to claim 33, wherein said step of obtaining the public key comprises the step of obtaining the public key from a trusted party.

36. A method according to claim 33, wherein said step of obtaining the public key comprises the step of obtaining the public key from the header.

37. A method according to claim 33, wherein said header includes camera information, and wherein said step of calculating a trial message digest comprises a step of calculating the trial message digest using the camera information.

38. A method according to claim 37, further comprising the step of obtaining an identity of the hashing function from the header.

39. An apparatus for validating authenticity of an image file containing image data and a header that includes a private-key-encrypted message digest together with unencrypted data including event data that went into forming the message digest, said apparatus comprising:

means for obtaining a public key complementary to a private key used to encrypt the message digest;

means for decrypting the private-key-encrypted message digest using the public key so as to obtain a message digest;

means for calculating a trial message digest using a hashing function the same as the hashing function used to form the private-key-encrypted message digest, and also using the unencrypted event data in the header; and

means for comparing the trial message digest to the decrypted message digest to determine the authenticity of the image file,

wherein the event data includes location data.

40. An apparatus according to claim 39, wherein the location data comprises GPS-derived data.

41. An apparatus according to claim 39, wherein the means for obtaining the public key comprises means for obtaining the public key from a trusted party.

42. An apparatus according to claim 39, wherein the means for obtaining the public key comprises means for obtaining the public key from the header.

43. An apparatus according to claim 39, wherein said header includes camera information, and wherein said means for calculating a trial message digest comprises means for calculating the trial message digest using the camera information.

44. An apparatus according to claim 43, further comprising means for obtaining an identity of the hashing function from the header.

45. An apparatus for validating authenticity of an image file containing image data and a header that includes a private-key-encrypted message digest together with unencrypted data including event data that went into forming the message digest, comprising:

a program memory for storing process steps executable to;

(1) obtain a public key complementary to a private key used to encrypt the message digest, (2) decrypt the private-key-encrypted message digest using the public key so as to obtain a message digest, (3) calculate a trial message digest using a hashing function the same as the hashing function used to form the private-key-encrypted message digest, and also using the unencrypted event data in the header, and (4) compare the trial message digest to the decrypted message digest to determine the authenticity of the image file, wherein the event data includes location data; and

a processor for executing the process steps stored in said memory.

46. An apparatus according to claim 45, wherein the location data comprises GPS-derived data.

47. An apparatus according to claim 45, wherein said step of obtaining the public key comprises the step of obtaining the public key from a trusted party.

48. An apparatus according to claim 45, wherein said step of obtaining the public key comprises the step of obtaining the public key from the header.

49. An apparatus according to claim 45, wherein said header includes camera information, and wherein said step of calculating a trial message digest comprises a step of calculating the trial message digest using the camera information.

50. A method according to claim 49, further comprising the step of obtaining an identity of the hashing function from the header.

51. Computer-executable process steps stored on a computer readable medium, said computer-executable process steps for validating authenticity of an image file containing image data and a header that includes a private-key-encrypted message digest together with unencrypted data including event data that went into forming the message digest, said computer-executable process steps comprising:

an obtaining step to obtain a public key complementary to a private key used to encrypt the message digest;

a decrypting step to decrypt the private-key-encrypted message digest using the public key so as to obtain a message digest;

a calculating step to calculate a trial message digest using a hashing function the same as the hashing function used to form the private-key-encrypted message digest, and also using the unencrypted event data in the header; and

a comparing step to compare the trial message digest to the decrypted message digest to determine the authenticity of the image file,

wherein the event data includes location data.

52. Computer-executable process steps according to claim 51, wherein the location data comprises GPS-derived data.

53. Computer-executable process steps according to claim 51, wherein said step of obtaining the public key comprises the step of obtaining the public key from a trusted party.

54. Computer-executable process steps according to claim 51, wherein said step of obtaining the public key comprises the step of obtaining the public key from the header.

55. Computer-executable process steps according to claim 51, wherein said header includes camera information, and wherein said step of calculating a trial message digest comprises a step of calculating the trial message digest using the camera information.

56. Computer-executable process steps according to claim 55, further comprising the step of obtaining an identity of the hashing function from the header.

57. A secure connection between a GPS receiver and a digital camera, whereby the digital camera can obtain secure GPS-derived data in correspondence to digital images obtained by the digital camera, comprising:

a private key encrypter in the GPS receiver, said private key encrypter for private-key-encryption of information corresponding to GPS-derived data;

a public key decrypter in the digital camera, said public key decrypter for public-key-decryption of the private-key-encrypted GPS-derived data; and

an interface between the GPS receiver and the digital camera for transmitting the private-key-encrypted GPS-derived data from the GPS receiver to the digital camera.

58. A secure connection between a GPS receiver and a digital camera according to claim 57, wherein said private key encrypter private-key-encrypts a message digest corresponding to the GPS-derived data.

59. A secure connection between a GPS receiver and a digital camera, according to claim 58, wherein the private key is secure with the GPS receiver, and wherein the public key is obtained from a trusted source and is complementary to the private key.