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Author Topic: Canon image data verification  (Read 2305 times)


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Canon image data verification
« on: October 08, 2013, 12:24:23 AM »

jvirta

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Re: Canon image data verification
« Reply #1 on: October 08, 2013, 01:34:43 AM »
Don't know if it is the answer, but the system had it flaws and was too easy to crack which means that it was useless as one could have modified the data and it would still have been verified as non-edited original by the verification software.

privatebydesign

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Re: Canon image data verification
« Reply #2 on: October 08, 2013, 01:48:43 AM »
It was overtaken, as jvirta says it was cracked, very embarrassingly, but also some SD card manufacturers came out with tamper proof write once cards that could be put into evidence so the forensic value of the Canon system disappeared.
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dgatwood

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Re: Canon image data verification
« Reply #3 on: October 08, 2013, 09:06:37 PM »
It was overtaken, as jvirta says it was cracked, very embarrassingly, but also some SD card manufacturers came out with tamper proof write once cards that could be put into evidence so the forensic value of the Canon system disappeared.

I would argue that a write-once card has no value in terms of forensic trust unless the card has a unique, tamper-proof serial number and you can prove that the card in the evidence locker was the one used to shoot the photos originally.  Otherwise, you can just write a new card once....

privatebydesign

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Re: Canon image data verification
« Reply #4 on: October 08, 2013, 09:25:43 PM »
It was overtaken, as jvirta says it was cracked, very embarrassingly, but also some SD card manufacturers came out with tamper proof write once cards that could be put into evidence so the forensic value of the Canon system disappeared.

I would argue that a write-once card has no value in terms of forensic trust unless the card has a unique, tamper-proof serial number and you can prove that the card in the evidence locker was the one used to shoot the photos originally.  Otherwise, you can just write a new card once....

You could argue that, I wouldn't care. It is the reason I had been told for the demise of the Data Verification Kit from Canon so I passed it along, I have no interest in either. Having said that I would expect something as basic as a unique serial number on an SD card to be easily implemented. Semi interestingly, I only heard of write once SD cards, not CF cards, and they were not cheap.

Edit: It seems even the WORM (Write Once Read Many) SD cards from SanDisc had a comparatively short life cycle too, 2008-2010, they are still available from third parties for $10 each but the biggest one they made was 1GB.
« Last Edit: October 08, 2013, 09:41:48 PM by privatebydesign »
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Mt Spokane Photography

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Re: Canon image data verification
« Reply #5 on: October 08, 2013, 09:41:01 PM »
It was overtaken, as jvirta says it was cracked, very embarrassingly, but also some SD card manufacturers came out with tamper proof write once cards that could be put into evidence so the forensic value of the Canon system disappeared.

I would argue that a write-once card has no value in terms of forensic trust unless the card has a unique, tamper-proof serial number and you can prove that the card in the evidence locker was the one used to shoot the photos originally.  Otherwise, you can just write a new card once....

I think that forensic photographers have a pretty good idea of what is acceptable as evidence, along with the data trail required.  Having a tamper proof card is just one part of the story, but its a very important part.

duydaniel

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Re: Canon image data verification
« Reply #6 on: October 08, 2013, 10:57:22 PM »
hmmm i always thought raw is original enough to prove authenticity.

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Re: Canon image data verification
« Reply #6 on: October 08, 2013, 10:57:22 PM »

Marsu42

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Re: Canon image data verification
« Reply #7 on: October 09, 2013, 05:24:45 AM »
It was overtaken, as jvirta says it was cracked, very embarrassingly

It was naive of Canon to think they could make that working, if there's a will there's a way - even if using asymmetric cryptography the private key has to be somewhere in the camera, so it will be found unless using extremely expensive high-security parts.

hmmm i always thought raw is original enough to prove authenticity.

No, if you can de-mosaic it you can re-mosaic it :-) ... But it doesn't matter, it's not difficult today to detect image modifications, a German computer magazine (c't/iX) had a series about it. The only way to fool the detection: Print the tampered original, and re-photograph it in a blurry/shaky way ... but as algorithms evolve also this probably won't work, just as they *might* some day come up with a affordable finger print detector that cannot be easily fooled :-)

Lichtgestalt

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Re: Canon image data verification
« Reply #8 on: October 09, 2013, 06:05:31 AM »
forensic experts donĀ“t care about such things.

just watch CSI las vegas.. i mean.. they use NIKON.

 ;) ;D

neuroanatomist

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Re: Canon image data verification
« Reply #9 on: October 09, 2013, 07:00:44 AM »
...they *might* some day come up with a affordable finger print detector that cannot be easily fooled :-)

They already have...the iPhone 5S.  :P
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Marsu42

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Re: Canon image data verification
« Reply #10 on: October 09, 2013, 07:47:06 AM »
...they *might* some day come up with a affordable finger print detector that cannot be easily fooled :-)
They already have...the iPhone 5S.  :P

That's what I was thinking about - one day after release the fingerprint sensor on the iPhone was fooled by the very same method that worked for years (text in German, but there's a video with English subtitles: http://www.heise.de/ct/artikel/Der-iPhone-Fingerabdruck-Hack-1965783.html)

Btw there is a nice Mythbusters episode about this, they try to fool a "never circumented before, ever, really" commercial sensor on a door with an even less elaborate method. And they discover that you just hold a bed sheet in front of you to beat a motion detector :-p

Mythbusters: Holy Sheet

Explanation here: http://www.securitymagazine.com/articles/mythbusters-are-busted-1

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Re: Canon image data verification
« Reply #10 on: October 09, 2013, 07:47:06 AM »