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Image Authentication

Discussion in 'Nikon DX DSLR Forum' started by TZ250, Aug 30, 2008.

  1. TZ250


    Jul 16, 2008
    Ohio, USA
    Please explain to me what 'image authentication' is. What information is authenticated? The D300 manual is vague on what it is, but it does tell how to turn it on.

    Once the image authentication is on, do you add photographer information from the PC, or is the information embedded in the image directly from the camera?

    I've searched for the answers, but I haven't found what I'm looking for.

    Thanks in advance! :smile:
  2. dking99


    Aug 19, 2008
    Rockville, MD
    You will be able to add your own name and company info to the EXIF info embedded in the photo. This means you can right click on the image, properties, advanced, and your information will show up along with the camera model, shutter f stop, etc...

    Its a good idea if you sell digital copies of your image...
  3. From a Nikon site
    "Image Authentication Software, designed exclusively for use with specific Nikon digital SLRs. This software enables the authentication of an image captured by the camera and can determine whether or not it has been altered since capture. Image data can be used as a critical link in the “chain of evidence” for verifying image authenticity by law enforcement and government agencies, the media, insurance companies and for a variety of other business applications. Nikon Image Authentication Software allows easy and secure authentication of images for a wide range of requirements.
    Image data as well as information attached to the image are verified to determine whether an image captured by the camera has been changed in any way. Verification results are displayed as a list on the screen of a personal computer, and images selected are displayed as thumbnails within the same screen."
  4. TZ250


    Jul 16, 2008
    Ohio, USA
    Thanks, guys. I appreciate the information.

    One more question. Is the Image Authentication information always added after the pictures are downloaded, or can the camera do that automatically?

    Thanks again! :smile:
  5. rgordin


    Jun 3, 2008
    Washington, DC
    I am new to the D300 but I think what you describe is Image Comment, p. 317 of the manual I have.
  6. TZ250


    Jul 16, 2008
    Ohio, USA
    Rgordin, thanks for the reply. I've seen the image comment, but that's different than the image authentication. I was just trying to learn about that and to find out if people use it. According to the friendly people here at the 'cafe', they do use image authentication. :smile:
  7. If it's not enabled in-camera at the time of the capture, I don't know how this authentication feature could be used in court to prove that an image has not been altered after it has been taken.

    Other than law enforcement, assurance and perhaps a few other specialized areas of photography where it is crucial to prove that an image has not been altered in any way, I don't see how this would ever benefit the usual photographer: think about it, if you tried to process your image to taste (adjust white balance, add vibrancy to the colors, sharpen, etc...), you would defeat the authentication. Why pay for it then?
  8. AviSys


    Mar 31, 2008
    Placitas, NM
    Yes, there would have to be a checksum produced at the time of capture, mathematically derived from the pixels, stored in the RAW file. Then, if any changes were made to the file, even one pixel, it would fail the test.

    Of interest would be, where is the data stored? There is a locked binary memo field in the EXIF -- maybe there?

    Nevertheless, I can see lawyers having a field day with this: "Is the algorithm public? If not, who has it? How do you know nobody else has it? How do you know the algorithm was not applied to a modified file, and that's what you are showing us? Any 16 year-old hacker could create a bogus image -- hell, they break into Bank of America every day!"
  9. Commodorefirst

    Commodorefirst Admin/Moderator Administrator

    May 1, 2005
    Image authentication is different from comment,

    Authentication is only for serious use of the tracing of alteration of images, and is only viable and authenticated on the first copy of the image, any manipulation to the image removes the authentication and creates a trail

    It is used as a forensic tool, and does greatly slow down the capture of images and the fps.

    It should not be used for normal photographic image uses.

  10. adrianaitken

    adrianaitken Guest

    It's not just for law enforcement - if you're a PJ and send in 'that' picture (Pulitzer prize winner) which people claim is photoshopped then you can prove you really did shoot it.

    I don't think it creates a paper trail, if you manipulate the raw files in say,Photoshop, then the IA field stays the same. If someone used the very expensive Nikon software to check the image, it'll just say it's been altered, not 'x added a person here and cloned out this tree'. I seem to remember reading somewhere though that things like WB can be altered OK, but things like the timestamp and bits of data which are checked.
  11. Commodorefirst

    Commodorefirst Admin/Moderator Administrator

    May 1, 2005
    good point about PJ work, and I said it created a trail, meaning altered indication, never mentioned paper. :wink: But I should have stated left an altercation indication instead of trail to be clearer.
  12. adrianaitken

    adrianaitken Guest

    Wade, I always say 'paper trial' - worked in finance for too long. Nowadays the 'paper trial' is normally electronic :smile:
  13. Commodorefirst

    Commodorefirst Admin/Moderator Administrator

    May 1, 2005
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