Seeing is not believing

Altering digital imagery is now ubiquitous. People have come to expect it in the fashion and entertainment world, where airbrushing blemishes and wrinkles away is routine. And anyone surfing the Web is routinely subjected to crude photographic mashups like the Palin hoax, whose creators clearly aren't interested in realism but in whatever titillation or outrage they can generate. Even as experts continue to develop techniques for exposing photographic frauds, new techniques for creating better and harder-to-detect fakes are also evolving. As in the battle against spam and computer viruses, it seems inevitable that the arms race between the forger and the forensic analyst will continue to escalate, with no clear victor. Improved image forensics will never be able to eradicate or prevent digital tampering, but these techniques can make it more time-consuming and difficult for forgers to ply their trade. Tomorrow's technology will almost certainly enable digital manipulations that today seem unimaginable, and the science of digital forensics will have to work hard to keep pace. It is my hope that these new techniques, along with a greater awareness of the technological possibilities and sensible updates in policy and law, will help the media, the courts, and the public contend with the exciting but often baffling events of our digital age.