Researcher’s Analysis of al Qaeda Images Reveals Surprises
Neal Krawetz, a researcher and
computer security consultant, gave an interesting presentation today at the Blac
kHat security conference in Las Vegas about analyzing digital photographs and video
images for alterations and enhancements.Using a program he wrote (and provided on the conference CD-ROM) Krawetz could print out the quantization tables in a JPEG file (that indicate how the image was compressed) and determine the last tool that created the image — that is, the make and model of the camera if the image is original or the version of Photoshop that was used to alter and re-save the image.
