Worried about Digital Evidence Tampering? 292
2marcus writes "As digital technology continues to improve and is used in more and more applications, the ease of tampering with digital files becomes more pertinent. This is especially important in the field of criminal justice, where even the appearance of possible impropriety can sway a jury. CNN has an article on the issues with digital photos being used for fingerprints and other forensics evidence."
Digital Camera Manufacturers have thought of this (Score:5, Informative)
So technology has answered, its back in the hands of law enforcement to present their case properly.
Re:Chain of custody (Score:2, Informative)
That is also why I applaud the Oregon State Police's efforts at ensuring chain of custody by keeping an encrypted version of the original image locked away on CD. It also makes any mods reproducible in front of a jury, if necessary.
The potential for modification doesn't scare me as much as the ability to permanently archive evidence. I can go back to a negative shot in 1930 and print it (provided it hasn't decomposed too badly). Will the same be true of digital formats?
Witnesses (Score:5, Informative)
Re:DIGITAL evidence ? (Score:3, Informative)
With analog, you end up with a dozen 'experts' with magnifying glasses who cant decide if its bigfoot or a guy in a gorilla outfit.
Besides, cases are built on actual physical evidence. That freak who kidnapped the little girl from the carwash will get the chair because of DNA and other evidence, not the surveillance footage.
Chain of Evidence (Score:4, Informative)
One way of hardening the chain is to burn the digital record onto a CD-R, with a least two witnesses and recording the serial number of the CD-R onto the evidence log.
Comment removed (Score:5, Informative)
Re:veripic (Score:2, Informative)
photographic evidence.... (Score:5, Informative)
Jury's, and judges consider the instant developed photos of the instamatic camera are considered unalterable because of how they are made
usually the oldest technology is the most accepted in the court of law.
Re:Only solution (Score:5, Informative)
It's not hard for experts to detect Photoshop fakery, even if amateurs can be fooled. If you move objects around in the picture, you'll never be able to get every cast shadow right, or get the lighting of the removed objects right. The analysis process that the experts use is analogous to ray tracing run backwards: given the images, figure out where the lighting is. Then boundaries between regions that have been altered and regions that have not come out clearly.
Furthermore, as its name implies, many of the Photoshop tools correspond to tricks that photographers have traditionally played in darkrooms, it just makes it easier.
Re:Wrong (Score:5, Informative)
What case was that?
Joseph Salvati ABC News [go.com]
A quick google [google.com] turns up other probable cases.
And it's not going to change until someone gets the guts to start bringing charges against cops and prosecutors who knowingly use false information, or withhold information.
We sell software (Score:3, Informative)
Re:Only solution (Score:2, Informative)
Unfortunately the benefits of the digital camera are lost then. If I wanted write once media, I would use film. On the other hand, I see where your trying to go with this in setting up a tamper resistant protection scheme. Even so, one could still do some elaborate tampering to bypass security methods. They'd almost have to do it, just for the challenge. Look at all the protection schemes people have developed in the past, only to be thwarted by a teenager with a bit of time on their hands.
my company is dealing with this right now (Score:2, Informative)
to make sure they are not altered, a MD5 checksum will be recorded at the time of scanning for each file. So, to verify later, you should be able to make sure the MD5s match.
right?
is there a better way?
"Forget photographs as evidence of anything..." (Score:3, Informative)
Now we can do it with Photoshop Elements on a home computer.
Yes, juries ''should'' be cautious in their approach toward photographic evidence. It was never true that "the camera doesn't lie," but the ease and inexpensiveness with which digital images can be altered certainly ought to alter the jury's Bayesian estimates of the likelihood that tampering could have occurred.
Canon has a no-tampering digital photo kit (Score:3, Informative)
Basically, the way it works is that the camera computes a cryptographically strong hash of the image file at the time the picture is taken and stores it on a tamper-proof secure card. The kit is specifically targeted at law enforcement.
Re:Only solution (Score:5, Informative)
I work in wholesale justice -- I do a lot of court-appointed work. There is no way that an expert will be approved in every case to authenticate or detect alterations of digital images. At the basic level of the legal system, the people who most need this sort of protection (accused criminals) will not be able to afford it.
I like the idea of digital photographs with some sort of cryptographic self-authentication. It would reduce the risk of cowboy cops faking evidence and putting it over on juries and judges. Someone needs to police the police, and this might help.
GF.
DOJ likes DD for Drive imaging (Score:3, Informative)
http://www.cftt.nist.gov/documents/Atlanta.pdf
They have been testing a bunch of programs, and so far dd on Free BSD has performed best:
http://www.ojp.usdoj.gov/nij/pubs-sum/203095.ht
Re:Only solution (Score:3, Informative)
Re:Only solution (Score:2, Informative)
No, just the opposite. I want more police departments using digital photographs. My girlfriend works in a 1 hour photo lab. She processes countless rolls of police evidence.
My biggest complaint is that she, making all of $6/hr, is exposed to some pretty gruesome pictures (You don't ever want to see some of the closeups.) We don't live in the boondocks, either. We live in a decent sized metro-detroit city, though it won't appear on any national maps.
It also pisses me off that so much money is wasted on these photographs. For a small investment, they could have digital cameras and a projector in the courtroom. There's no reason to print all 200 images on the same scene.
The last thing is that few people realize how likely it is for whole batches of negatives to get ruined. Those machines are far from automated and the people operating them are far from professionally trained. One slip up and a whole murder case is screwed.
CD-R? (Score:3, Informative)
The article does bring up a very good point:
1. Light ---> lens ---> Negative ---> Print.2. Light ---> CCD ---> Onboard Software ---> Writable Media ---> Computer.
I'd rather the police go with choice #1 for the time being.
And why aren't they buying their polaroid film from India?
How to guarantee digital images are the real deal (Score:3, Informative)
Canon has a "Data Verification Kit" (DVK-E2) for law enforcement and related types that worry about tampering.
From DPReview's copy of Canon's press release, "The kit consists of a dedicated SM (secure mobile) card reader/writer and verification software. 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."
So it looks like, when you combine the EOS-1D/1Ds w/ the "Secure Mobile" card and put the camera in to a special data verification mode, it probably generates a MD5 or similar hash for each image that is generated.
This seems to be a fairly obvious way to defeat cries of tampering, although I have no idea how well this software/hardware has been pushed. Perhaps there is a hole somewhere? Hard to say. Hopefully Canon will release similar products for all of their higher-end (300D and up) cameras.
Re:Only solution (Score:2, Informative)
This [goodbrush.com] is an original plate photograph that is handed to the Matte Painter.
And this [goodbrush.com] is what he's done with it.
Matte Painters are extremely good at this, and have an amazing amount of knowledge about light and how it works on various surfaces.
I really wonder how far such a painting would go in fooling an "expert" given its painted by an expert in the first place.