Anti-forensics of Median Filtering and Contrast Enhancement

Abstract Digital images can be convincingly edited using image editing tools. In order to identify such image processing operations, various forensic techniques have been proposed. In response, anti-forensic operations designed as counter-measures have been devised. In this paper, we propose an anti-forensic technique to counter spatial domain forensic detectors and demonstrate its accuracy on popular image manipulation operations such as median filtering and contrast enhancement. The integrated anti-forensic attack is formulated as an optimization problem. The proposed optimization modifies the image so as to incorporate the median filtering or contrast enhancement operation while ensuring that its spatial characteristics do not change significantly. Through a series of experiments, we prove that the proposed algorithm can severely degrade the performance of median filtering and contrast enhancement detectors. The proposed algorithm also outperforms popular anti-forensic algorithms.