Scalar DC–QIM for Semifragile Authentication
Jean-Philippe Boyer, Pierre Duhamel, Jacques Blanc-Talon · IEEE Transactions on Information Forensics and Security · 2008
Semifragile watermarking can be used to detect illegal and local manipulation, while being robust toward legal processings such as lossy compression. The aim of this work is twofold: 1) we first formalize this semifragile authentication problem by proposing an appropriate payoff: by considering the watermark as an integrity stamp (i.e., its detectability stands as an integrity evidence), a natural game cost is the false-alarm probability which still detects the watermark in a tampered content and 2) this approach is further applied to find the optimal power allocation across parallel additive Gaussian channels of a dithered distortion compensated scalar quantization-based scheme against substitution attacks. The results are specialized to design an efficient discrete cosine transform (DCT) semifragile image watermarking system which allows detecting substitution attacks despite JPEG compression.