1Ramkumar M, Akansu A N. Image watermarks and counterfeit attacks: some problems and solutions. In: Proceeding on Content Security and Data Hiding in Digital Media Conference Newark, NJ, 1999,102 ～ 112
2Peticolas F A P, Anderson R J, Kuhn M G. Attacks on copyright Marking system. IN Second International workshop on Information Hiding, Portland, Oregon,U. S. A, April14 ～ 17,
