Photographs contain digital fingerprints

 

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By Stuart Turton

Posted on 18 Nov 2008 at 12:14

A new digital forensic technique could allow photographs to be traced back to the camera they were taken with, even after they've been stripped of their metadata.

The technique was discovered by researchers at the Polytechnic University in Brooklyn, who found that every digital camera leaves a unique signature in every pixel it captures.

This is the result of the built-in demosaicing software which adapts the colour and brightness levels of every pixel so that it meshes with the pixel next to it.

According to the researchers, this demosaicing software is often unique to the camera model as it has been tailored to work with the lens and other bespoke components of the device.

The researchers found that by examining the values associated with the pixels they can identify the demosaicing software used to create them in 90% of cases, allowing them to tie photographs to specific models.

Although the technique can't narrow photographs down to specific cameras, the researchers argue it could still have an application in detective work by narrowing down the period in which the camera was sold, and in which countries it was available.