Abstract: To improve the security of dual self-recovery watermark, a chaos-based dual selfrecovery watermark scheme for image authentication was proposed in this paper. In the proposed scheme, the chaotic map was first adopted to encrypt the dual watermark data, and then the data were embedded into the image block of less significant bits. And then the authentication data of each block was randomly generated with reference to its content and the recovery watermark embedded according to the chaotic mapping. Theoretical analysis and simulation results show that the proposed scheme can not only maintain the good tamper recovery quality and invisibility of dual self-recovery watermark, but also improve the security against the only-content tampering attack and the dictionary searching attack.

Key words: image authentication, dual watermark, chaos, security, tamper recovery quality

摘要： 为提高图像自恢复双水印算法的安全性，提出一种基于混沌的安全双水印算法。该算法首先利用混沌映射将双水印信息加密后再嵌入其他图像块的低位，然后结合图像块内容和嵌入在图像块低位的恢复水印信息，利用混沌映射随机生成用于检测图像块真实性的认证数据。理论分析和实验结果表明该算法在保持篡改恢复质量和不可见性的基础上，有效提高了自恢复双水印算法抵抗内容篡改攻击和字典搜索攻击的能力。

关键词: 图像认证, 双水印, 混沌, 安全性, 篡改恢复质量