为进一步加强当前数字水印的安全性,对得到广泛研究的自适应水印中的可反向性问题进行了探讨.首先对水印体制进行了分类和抽象.随后基于自适应水印对植入水印和调节因子的形成没有约束的前提,对存在的可反向性和半可反向性问题,以及由此引起的反向工程攻击和半反向工程攻击进行了定义、分析和实验,指出了它们对相关数字所有权验证的干扰甚至否定作用.最后得出了对植入水印和调节因子的形成都必须进行约束的结论,指出了一些自适应技术本身的不可反向性对安全性的增强作用.让植入水印和调节因子的形成单向依赖于原始媒体,并充分利用人类感知系统,使水印体制对上述攻击具备抵抗性,增强了数字所有权验证的可靠性.%To further enhance the security of the present digital watermarking, the reversibility of widely researched adaptive watermarking is investigated. First, watermarking schemes are classified and generalized. Then, on the assumption that adaptive watermarking places no constraint on the formation of watermarks and scaling factors, the reversibility and quasi-reversibility, together with their resulting reverse and quasi-reverse engineering attacks, which could disturb or even overturn the ownership verification, are defined, analyzed and illustrated. Finally, the necessity of placing constraints on the formation of watermarks and scaling factors is concluded, and the essential irreversibility of some adaptive technologies, which can be used to enhance the security, is pointed out. Making watermarks and scaling factors one-way dependent on original data, and exploiting the human perceptual system, help watermarking become resistant to the above attacks and more reliable in ownership verification.
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