Applying interest operators in semi-fragile video watermarking

In this article we present a semi-fragile watermarking scheme for authenticating intra-coded frames in compressed digital videos. The scheme provides the detection of content-changing manipulations while being moderately robust against content-preserving manipulations. We describe a watermarking method based on invariant features referred to as interest points. The features are extracted using the Moravec-Operator. Out of the interest points we generate a binary feature mask, which is embedded robustly as watermark into the video. In the verification process we compare the detected watermark with the interest points from the video to be verified. We present test results evaluating the robustness against content-preserving manipulations and the fragility in terms of content-changing manipulations. Beside the discussion of the results we propose a procedure to provide security of the scheme against forgery attacks