Seeing Is Not Believing
Inexpensive digital cameras and simple software have made it easy to convincingly doctor photographs, and such fake images can tarnish reputations, manipulate political opinion, fool security, and be mistaken for legitimate evidence in judicial proceedings while discounting the authenticity of actual proof.
The profound ignorance of the problem is only surpassed by the lack of people working on solutions, although effective methods for preventing and spotting digital photo tampering are starting to emerge, primarily through military and law enforcement-directed efforts.
Dartmouth College computer scientist and digital forensics expert Hany Farid has developed algorithms that scan images for statistical data patterns that certain forms of doctoring leave behind, but the software cannot accurately assess the compressed and low-resolution images the Internet is rife with.
Another approach is to tag photos with digital watermarks as proof of legitimacy, and Jessica Fridrich of State University of New York Binghamton is developing a camera that affixes watermarks as well as biometric identifiers for the photographer, which could be very useful in court cases where the genuineness of photos is disputed.
Another potentially significant future development is digital ballistics, in which the specific camera that shot a digital photo or photos could be identified by software that detects patterns left by distinctive imperfections in the camera’s light sensor.
Farid, however, is resigned to the fact that no anti-forgery technique is foolproof. Determined and resourceful forgers will always defeat even the most advanced security measures, and he believes the best recourse is to keep prevention and detection methods refined enough to thwart the majority of forgers.
Abstracted by the National Law Enforcement and Corrections Technology Center(NLECTC) from the Popular Science (10/05) Vol. 267, No. 4, P. 70; Casimiro, Steve .
