U of S | Mailing List Archive | alt-photo-process-l | Re: "evidence tampering"

Re: "evidence tampering"

In addition to detection of  forgery through the software trail (which nerds
can probably edit quite easily), recent study by Jessica Fridrich and others
has established that:
    "Every original digital picture is overlaid by a weak noise-like pattern
of pixel-to-pixel non-uniformity.

    "Although these patterns are invisible to the human eye, the unique
reference pattern or 'fingerprint' of any camera can be electronically
extracted by analyzing a number of images taken by a single camera.

    "That means that as long as examiners have either the camera that took
the image or multiple images they know were taken by the same camera, an
algorithm developed by Fridrich and her co-inventors to extract and define
the camera's unique pattern of pixel-to-pixel non-uniformity can be used to
provide important information about the origins and authenticity of a single

refer http://www.eurekalert.org/pub_releases/2006-04/bu-bur041806.php

Don Sweet

----- Original Message ----- 
From: "Eric Neilsen" <ejnphoto@sbcglobal.net>
To: <alt-photo-process-l@usask.ca>
Sent: Sunday, September 24, 2006 3:15 AM
Subject: RE: "evidence tampering"

> Wow, I missed this thread. Judy the file can have information attached to
> as well that will tell you all the changes. If one was intent on making
> things up through digital manipulation it would be hard to absolutely
> it but here come the "If it smells like a... and walks like a... " .
> PS will give you a list of actions taken toward the file and I don't mean
> actions from the action palette but any retouch, opening, closing, etc.
> There was in fact, on one list that I participate, a desire to share the
> file info so that other could see what you did to make the image.
> Eric
> > -----Original Message-----
> > From: Judy Seigel [mailto:jseigel@panix.com]
> > Sent: Wednesday, September 06, 2006 9:43 PM
> > To: alt-photo-process-l@usask.ca
> > Subject: "evidence tampering"
> >
> >
> > On Tue, 5 Sep 2006, Camden Hardy wrote:
> >
> > > "...calls for works that specifically question the nature of visual
> > > documentation, including its definition, potentials, semiotic systems,
> > and
> > > social resonances in a Post-Modern world."
> >
> > > I interpret this as saying, "so photography has the ability to distort
> > the
> > > truth...now what are we, as photographers, going to do about it?"
> >
> > A book on this topic was published about 7 years ago, I think by Frank
> > Richie (or someone like that)... I have it around here somewhere, but it
> > struck me as more or less re-laboring the obvious & only partially true,
> > anyway. (Basically his point was that digital made trickery possible,
> > IMO, as noted, 'twas ever thus, just not so easy.)
> >
> > However I have a question.  There was a fair amount of police chicanery
> > with videotapes of arrests during the Republican National Convention in
> > NYC in 2004 -- actually quite amusing, if police lies and evidence
> > tampering strike one's funny bone. Independent videotapes were located
> > that showed the deleted parts, as reported at several points by the NY
> > Times. But then, sometime last year (I have the clip, just not in front
> > me) the Times mentioned, almost in passing, that something like 400
> > HUNDRED !) police prosecutions had to be dropped because the tapes had
> > been found to be "improperly edited."  (I think Mark would add "heh heh
> > heh.")
> >
> > I took that to mean, tampering had been detected again -- on the
> > videotape. My question, which I figure some of the digital mavens around
> > here would know, is, can you see by examining a jpeg (or digital camera
> > file) if that's been altered as apparently you can with video?
> >
> > I would assume if it's been saved in a different format, editing would
> > not be detectable. But if it were saved in the same jpeg format ????
> >
> > (Just wondering, not planning anything.)
> >
> > Judy