关键字符双重验证的Word文档脆弱水印方法

为提高文档水印方法的篡改检测性能和安全性,设 计一种关键字符双重验证的Word文档脆弱 水印方法。首先记录文档中的关键字符和非关键字符,将每个字符生成的8比特水印信息 嵌入自身字符 的特殊属性里以抵抗一般篡改；为提高检测关键字符篡改的能力,将关键字符生成的8比 特水印信息作 为第二重水印信息嵌入到非关键字符的其它特殊属性里以抵抗拼贴攻击,从而实现对关键字 符的双重验证； 通过统计实验,讨论了水印嵌入在字符特殊属性中对文档大小的影响。实验结果表明,在字 符的特殊属性 中嵌入水印能增加含水印文档的安全性,在非关键字符中嵌入双重水印能提高算法的篡改检 测性能。

A fragile Word document watermarking based on critical-character double verifications

To improve the tampering detection performance and the security of Word document watermarking method,a fragile Word document watermarking scheme based on critic al-character double verifications is proposed.In this method,all characters in the Word document are divided into the critical characters and non-critical ones.The 8bits watermar k data generated by each character are embedded into the special properties of the same character for the purpose of resisting g eneral tampering.In order to improve the tampering detection performance for the critical chracters.the 8bits watermark data generated by the critical characte r act as the second watermark data,which are embedded into the special propertie s of the other non-critical chracter so as to resist collage-attack.When this solution,it can realize the double verifications of the critical character.In ad dition,we also discuss the impact of watermark data embedded into the special pr operties of the character on th e size of Word document by statistical experiments.All those experimental result s show that the watermark data embedded into the special properties can improve the security of the watermarked Word document,and the dual watermark data which are embedded into the critical chracter can improve the tampering detection perf ormance greatly.