Re: "evidence tampering"

To: alt-photo-process-l@usask.ca
Subject: Re: "evidence tampering"
From: Judy Seigel <jseigel@panix.com>
Date: Wed, 18 Oct 2006 23:34:36 -0400 (EDT)
Comments: "alt-photo-process mailing list"
In-reply-to: <025001c6e35f$ae048d50$0101a8c0@east>
List-id: alt-photo-process mailing list <alt-photo-process-l@sask.usask.ca>
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Reply-to: alt-photo-process-l@usask.ca


On Fri, 29 Sep 2006, Don Sweet wrote:

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
image."

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

Thanks Don -- that's fascinating (and almost reassuring).

J.