Protection of wavelet-based watermarking systems using filter parametrization

We discuss wavelet filter parametrization as a means to add security to wavelet-based watermarking schemes. It turns out that our proposed scheme is resistant to unauthorized detection and unauthorized removal attacks and is equally robust as compared to the use of standard wavelet filters in case the underlying watermarking scheme is spread-spectrum based. Quantization-based watermarking techniques are not suited to be enhanced by this approach. We assess the security, quality and robustness of our approach in the light of four selected watermarking algorithms. Furthermore, we present an attack tailored to exploit a common weakness in image-adaptive watermarking and propose filter parametrization as a suitable countermeasure. (C) 2003 Elsevier B.V. All rights reserved.