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Worried about Digital Evidence Tampering?
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."
So technology has answered, its back in the hands of law enforcement to present their case properly.
Any form of physical evidence can be tampered with. That's why the chain of custody is such an important concept.
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 credibility has been under debate for years. Witnesses can be influenced by suggestive questioning, their own backgrounds and prejudices, or the amount of sleep they have had on a given day. And how do you quantify or qualify that kind of tampering? Witness testimony has been used for millenia. No evidence is foolproof. The problem is 1. to know what kind of tampering can be done and be aware and wary of it and 2. to get the trust of the public in that type of evidence so it can be admitted, falible or not.
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You can prove through cryptographic means, md5 sums, etc, that the odds a digital file has been tampered with are billions-to-one. Some cameras designed for LEOs have such stuff built in, you can prove that the file hasnt changed since the camera took it.
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.
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No, law enforcement officers are required to maintain strict control and tracking of evidence now ("Chain of Evidence") to try and prove the evidence has not been tampered with. The mutability of digital records adds extra considerations, in some cases.
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.
Sure, it's a little easier, but it's not something we suddenly can do that we weren't able to do previously.
You are not alone. This is not normal. None of this is normal.
sorry, bad link: http://www.veripic.com/certified.htm
I was told by a lawyer to get photographic evidence , not in digital, or film but Instant film format.
/developed.
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.
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.
at least one case where the FBI insured that an innocent man was convicted of murder and sent to prison in order to protect their own informant.
What case was that?
Joseph Salvati ABC News
A quick google 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.
at BrightNoise Inc that works with IP based cameras and video "servers" to stream images and detect motion, alarms, etc in sensitive areas . One of the biggest concerns I have had is tampering with jpegs or avi files exported from these softwares. AFAIK none has been challenged in a court of law here in the states, but we have had several schools and companies use it as proof of guilt for thieving and extortion!! The approach Milestone took was to make it exceedingly difficult to tamper with the original recording but allow exports. I train users to immediatly remove the original drives or enter server when there is an event of serious enough magnitude, lets face it whats a few thousand dollars when your talking about firing someone or worse? Personally I would like to see water marks or some embedded checksum in the images.
Si vis pacem, para bellum! For evil to succeed good men need only do nothing!
Some solid state memory card company should start making write once memory that would work in a digital camera.
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.
we have to scan lots of birth certificates. 7 million or so into single page tiffs.
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?
...was, if I recall correctly, the headline on a story that appeared in Whole Earth Review in the 1980s. The article concerned Scitex's image-processing workstations, and their use to move pyramids on the cover of Time Magazine in order to achieve a more pleasing composition, to add or remove people from a picture, and so forth and so on. The cover, as I recall, showed a UFO landing on the street where Whole Earth's offices were located.
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.
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Look here: http://www.dpreview.com/news/0401/04012903canondvk e2.asp
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.
Kaa
Kaa's Law: In any sufficiently large group of people most are idiots.
It's not hard for experts to detect Photoshop fakery, even if amateurs can be fooled.
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.
Lots of petrified grits
NIST has a test spec for drive imaging software for forensic use.
m
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
"As God is my witness, I thought turkeys could fly." A. Carlson
If I can be modded down for being a troll, can I be modded up for being an orc, or a balrog?
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.
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?
[Fuck Beta]
o0t!
http://www.dpreview.com/news/0401/04012903canondvk e2.asp
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.
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This is an original plate photograph that is handed to the Matte Painter.
And this 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.