A general attack method for steganography removal using pseudo-CFA re-interpolation

Watermarking and steganography are two of the most researched topics in multimedia forensics. However, easy availability of tools and technology has made their misuse a serious concern. To counteract this development some effective tools are necessary to remove malicious steganography. In this work, we introduce a novel watermark attack method which can destroy hidden information embedded in images based on the principle of re-interpolation of Color Filter Array (CFA) artifacts. In digital cameras and scanners, CFA filters are used to acquire low-resolution physical color channel information and produce a high-quality image by subsequent interpolation. We propose to emulate a similar scheme in which image information is removed and reconstructed through interpolation and thereby destroy any hidden information without impairing the visual quality. Most importantly, our presented method is general and does not assume any knowledge of the used watermarking methods, the hidden message or the host image.