RESOLVING RIGHTFUL OWNERSHIPS WITH INVISIBLE WATERMARKING TECHNIQUES - LIMITATIONS, ATTACKS, AND IMPLICATIONS

Digital watermarks have been proposed in recent literature as a means for copyright protection of multimedia data, In this paper we address the capability of invisible watermarking schemes to resolve copyright ownership. We show that, in certain applications, rightful ownership c annot be resolved by current watermarking schemes alone. Specifically, we attack existing techniques by providing counterfeit watermarking s chemes that can be performed on a watermarked image to allow multiple claims of rightful ownership. In the absence of standardization and sp ecific requirements imposed on watermarking procedures, anyone can cla im ownership of any watermarked image. In order to protect against the counterfeiting techniques that we develop, we examine the properties necessary for resolving ownership via invisible watermarking, We intro duce and study invertibility and quasi-invertibility of invisible wate rmarking techniques, We propose noninvertible watermarking schemes, an d subsequently give examples of techniques that we believe to be nonqu asi-invertible and hence invulnerable against more sophisticated attac ks proposed in the paper. The attacks and results presented in the pap er, and the remedies proposed, further imply that we have to carefully reevaluate the current approaches and techniques in invisible waterma rking of digital images based on application domains, and rethink the promises, applications and implications of such digital means of copyr ight protection.