Digital Cameras Have Digital Fingerprints
From EurekAlert (American Association for the Advancement of Science):
Child pornographers will soon have a harder time escaping prosecution thanks to a stunning new technology in development at Binghamton University, State University of New York, that can reliably link digital images to the camera with which they were taken, in much the same way that tell-tale scratches are used by forensic examiners to link bullets to the gun that fired them. . .
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 . . . 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.
Source: Boing Boing