A significant effort has been put in designing watermarking algorithms during the last decade. But today, the watermarking community needs some advanced attacks and fair benchmarks in order to compare the performances of different watermarking technologies. Moreover attacks permit to find the weaknesses of an algorithm and consequently trigger further research in order to overcome the problem. This state of mind motivates the creation of the European Certimark project. After a short definition of the keyword dewatermarking, we present an original attack based on self similarities. This attack is then put to the test with three different publicly available watermarking tools. Finally we shortly discuss the feasibility of a generic attack i.e. a dewatermarking attack which should succeed in removing whatever watermark inserted by whatever watermarking tools.
Christian Rey, Gabriela Csurka, Gwenaël J. Do