Posted on 22 March 2010

Paper details:

Digital image forensics is a relatively new field that has only become popular within the last seven years. A newer body of research involves anti-forensics — methods of processing images that disguise evidence of earlier image processing or tampering. By altering the forensically significant properties in an image, existing image forensic systems may be rendered useless. Like many areas of security, we benefit from the study of anti-forensics by understanding the attacks that are most likely to occur before they actually do. Then, we can refine our image forensic systems further.

Earlier, our group proposed the first forensic system that identifies which compression method was used upon a digital image. In this paper, we propose an anti-forensic method for defeating the identification of JPEG compression in an image. Our method alters the intrinsic fingerprint of JPEG-compressed images in the transform domain such that the attacked image is perceptually similar to the image before attack. To our knowledge, this work is the first to propose a method specifically designed to defeat compression identification systems, and we anticipate that more work will follow.