Digital image watermarking: issues in resolving rightful ownership
In the literature many strategies for attacking and subverting a watermark have been presented. Such attacks suggest that the ability to embed non-erasable watermarks does not necessarily imply that the watermarking scheme can be used to establish ownership. The main aim of this paper is to formulate necessary and sufficient requirements for a watermarking scheme to be able to resolve rightful ownership. It is shown that some of the popular schemes proposed in literature for watermarking images do not satisfy these requirements. Finally, we show that a modification of a watermarking scheme in literature (Piva et al., 1997) performs satisfactorily.