The watermark template attack

This paper presents a new attack, called the watermark template attack, for watermarked images. In contrast to the Stirmark benchmark [1 -2], this attack does not severely reduce the quality of the image. This attack maintains, therefore, the commercial value of the watermarked image. In contrast to previous approaches [3-4], it is not the aim of the attack to change the statistics of embedded watermarks fooling the detection process but to utilize specific concepts that have been recently developed for more robust watermarking schemes. The attack estimates the corresponding template points in the FFT domain and then removes them using local interpolation. We demonstrate the effetiveness of the attack showing different test cases that have been watermarked with commercial available watermark products. The approach presented is not limited to the FFT domain. Other transformation domains may be also exploited by very similar variants of the described attack.