Return of ambiguity attacks
Scott A. Craver · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2002
The ambiguity attack, or invertibility attack, was described several years ago as a potential threat to digital watermarking systems. By manipulating the invertibility of watermark embedding, one could negate or subvert the meaning of a copyright mark. These attacks were easily prevented, however, with the appropriate application of one-way functions and cryptographic hashes in watermarking protocols. New research in watermarking, however, has caused the ambiguity attack to resurface as a threat, and this time it will not be as easy averted. Recent work in public-key watermarking create scenarios in which one-way functions may be ineffective against this threat. Furthermore, there are also positive uses for ambiguity attacks, as components in watermarking protocols. This paper provides an overview of the past and possible future of these unusual attacks.