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Digital Camera Image Verification

Posted by michael on from the signed-sealed-and-delivered dept.

Polo writes "While reading dpreview, I noticed that among several new products, Canon has announced a Digital Image Verification Kit to prove that an image taken by a particular camera has not been modified. It's disturbing to think about the conditions that would allow digital images to be accepted in a courtroom. I guess one defense would be to figure out how to 'verify' a photo of shark attack..."

7 of 255 comments (clear)

  1. Run around by MacFury · · Score: 5, Funny

    1.) Take picture
    2.) Photoshop picture
    3.) Print picture
    4.) Take picture of printed picture :-)

  2. won't work by contrasutra · · Score: 5, Insightful

    It won't work. From everything I've seen, attempts to verify ANYTHING digital will be cracked within a week or three.

    1. Re:won't work by contrasutra · · Score: 5, Informative

      Haven't read the gnupg.org website? From the front page:

      GnuPG's ElGamal signing keys compromised (2003-11-27)
      A severe problem with ElGamal sign+encrypt keys has been found. This leads to a full compromise of the private key.

  3. Re:Canon by Shakrai · · Score: 5, Insightful
    To everyone out there: you are an idiot if you buy a camera that does not support CompactFlash. You'll end up paying twice as much for the media.

    We have that interesting problem at work (Insurance Agency, which is half the reason this article caught my eye) -- we need digicams to do photo inspections of property or automobiles. All of our CSR workstations have CompactFlash readers. Half the new digicams out there don't use CF anymore -- which automatically takes them off my shopping list when I need to get new cameras.

    I'd also add to your statement that you are an idiot if you buy a camera that doesn't take standard AA (or AAA) batteries. We also have several sets of NI-MH batts and chargers -- I refuse to buy a digicam with propriety batteries. I can't count how much money and aggravation the standard formats of CF and AA NI-MH batts have saved me -- both on a business and personal level.

    --
    I want peace on earth and goodwill toward man.
    We are the United States Government! We don't do that sort of thing.
  4. What a joke by Rosco+P.+Coltrane · · Score: 5, Insightful

    When the appropriate function (Personal Function 31) on the EOS-1D Mark II or EOS-1Ds is activated, a code based on the image contents is generated and appended to the image. When the image is viewed, the data verification software determines the code for the image and compares it with the attached code. If the image contents have been manipulated in any way, the codes will not match and the image cannot be verified as the original.

    Note to self: run the signing software *after* altering the image. If the image was alrady signed, display it, take screenshot, alter the image, and re-run the signing software.

    --
    "A door is what a dog is perpetually on the wrong side of" - Ogden Nash
  5. Re:Not just court rooms by S.Lemmon · · Score: 5, Funny

    Because, as we all know, tabloids have a unwavering commitment to the truth! :-)

  6. Re:It's called MD5 (?) by jdbarillari · · Score: 5, Interesting
    So it's basically an MD5 (or equiv hashing method) of the image at the time it's taken? Too bad -- I thought they had a unique idea to verify images that had already been taken.

    [snip]

    What's to stop me from editing the MD5sum on the image and the smart media (it's presumably read/write)?

    Obviously, just storing the checksum of the image in the EXIF headers (or somewhere else) won't work -- you could just modify the image and calculate a new checksum. One variant on that scheme that would work (reasonably well) would be the following: each camera would be assigned a RSA private key. Canon would keep a record of which key was assigned to which camera (by associating it with the camera's serial number). The private key would be stored in a tamper-resistant chip on the camera's logic board. The camera could then digitally sign all of the images it captures. If the camera saved both its serial number and the digital signature in the EXIF headers of each image (or the JPEG comments, or whatever), a third party who wanted to verify the image could go to the Canon website, get the public key for that serial number, and verify the digitial signature.

    The weak point is in the 'tamperproof' chip -- research on smart cards has shown that virtually any so-called 'tamperproof' security system can be cracked. A court could demand to see one's camera (to ascertain that it had not been altered), but some smartcard attacks (such as those based on timing or power consumption) don't even need to modify the card to get at the key -- some of these attacks might translate to cameras, as well. It would be possible to provide pretty good image verification with this system. But a determined attacker could break it.