Computers, Court, and Fingerprints

Degrees writes "Should Law Enforcement be allowed to Photoshop fingerprints? That is the question posed in this article in the South Florida Sun-Sentinel. The suspect is charged with murder, and the evidence was circumstantial before the fingerprint enhancment. At the end, the crime scene investigators say they want encrypted cameras. The implication is they want DRM-enabled digital cameras with software for full audit-trail capability. Would that make the Photoshoping more credible? Would DRM cameras be a good thing for Joe Citizen?"

Comments

woah!

[RyLaN]

I could to that!! Get a print of my enemy, photoshop it and presto, we've got a conviction! Do the judges have any idea what can be done with Photoshop in the hands of someone who has used it before?

This is NOT DRM

[ChaosDiscord]

DRM is about taking options away from users. This is about providing users with a new option: a strong audit trail. You can make a copy of the image using non-auditing software, but that copy of the image would lose it's "seal of approval." The original would remain valid. The end result: cops can make any copies and image manipulations they want that may help them solve a case. But in court they'll only be able to present images with the valid audit trail, ensuring that the image was never mishandled and clearly showing what manipulations were done to it. It sounds like a great idea and I strongly support this option for users. (I am suspicious that it may not be possible... but I'm happy to let people try.)

This is not how photographic evidence works

[Bruce Perens]

The potential to fake a photograph has existed since the earliest days of photography. The veracity of the photograph or other scientific evidence rests on the oath taken by the photographer and other technicians involved. They are not asking for DRM, but for a digital signature generated by the camera and attesting to the time and other circumstances of the photograph. Auditing the image-processing is possible, given certified software and a circumscribed list of permitted operations. Some form of "trusted computing" could be used to avoid trivial circumventions of the list of allowed operations.

Note that this is "trusted computing" in service of the owner of the computer (in this case the police department and department of justice rather than the individual operator). The fundamental difference is that the owner of the computer is the one asking for the trusted service, rather than some other entity that does not trust the owner of the computer.

Bruce

Re:This is not how photographic evidence works

[BWJones]

The potential to fake a photograph has existed since the earliest days of photography.

This is certainly true and for a decent review, check out Dino A Brugioni's book, Photo Fakery: The History and Techniques of Photographic Deception and Manipulation. ISBN: 1574881663

Dino served as one of the CIA's senior photographic interpreters and the book is a decent review.

As far as DRM and how digital image management could work, see my other comment regarding the solution to DRM issues and certification of images.

Re:I saw this on tv

[Ibag]

I don't think that the question is whether this should be legal. The question is if evidence gathered in this way should be admissable in court. While this isn't the same as the cops taking evidence from your house without a warrent, you do have to worry about the accuracy of the technique and whether it should be allowed in court. They mention in the article about going in and digitally removing "interference" like weaves of fibre. Who is to say that the removal technique is good enough to recover the fingerprint exactly? What if the removal process adds/subtracts features from the fingerprint itself to the point that it appears to be a match but might not be?

It seems to be a useful technique for gathering evidence to find a suspect, but I'm not sure that I'd want it to be key evidence for a conviction.

Zero Post ??

[HughsOnFirst]

That's funny, I posted a link to the appropriate info yesterday, here it is again

Here is a good article that covers a lot of this
The "Authenticity Crisis" In Real Evidence
Scientific Evidence Review
10.1.2001

You might also be interested in the KODAK Picture Authentication Module [kodak.com] which uses PKI in a camera.

If I post before the story goes up is that a "Zero Post "?

Having been involved in traditional analogue photography for 30 years, I can tell you that I'd trust one of those Kodak cameras more that say a 35 mm Ektachrome Transparency, or worse yet, a color print. A while back Polaroid was blowing out a digital printer that output on spectra film for 30 bucks. I considered buying it for all sort of practical jokes and parking ticket disputes.

Re:"Enhanced" evidence

[Planesdragon]

Hmm, you can't really use it to get leads either. Any evidence that comes from inadmissable evidence is inadmissable itself.

I believe that you're wrong.

If you're given an anonymous tip, or someone takes a lie dectector test, you can't use these as evidence--but you CAN use them to get evidence.

Anything that comes from ILLEGAL police procedure is tainted. Not just inadmissable evidence.

Re:I saw this on tv

[Reziac]

Well, that depends. The customized filter could be rigged to only enhance certain traits that are known to be part of, but NOT EXCLUSIVE TO, say, fingerprint ridges. So you run the image thru the filter and suddenly, because the existing data fell into the trigger range, pixels get enhanced that shouldn't have been.

Having amused myself by mixing filters and data in all sorts of weird ways, I can tell you that often the results are not simply enhancement. Data disappears, artifacts appear, either of which could create spurious fingerprint ridges. So aside from the possibility of simple pixel painting, it is open to abuse.

I don't think the principle is bad, but rigorous standards would have to be developed and applied, including a complete audit trail (and incremental files) for each image.