A semi-fragile watermarking scheme for content authentication of chinese text documents

At present, the research on content authentication of text documents has become the focused problem. In this paper, a novel semi-fragile text watermarking scheme is proposed for content authentication of Chinese text documents. In this method, the host document is divided into two text blocks by utilizing the thought of Chinese mathematical expression. Two watermarks generated by using the chaotic encrypting algorithm to encrypt the hashing value of the text document with two different keys respectively, are embedded into the two text blocks. These two different keys are generated by computing the frequency and stroke numbers of Chinese characters of two different text blocks. When the content of the watermarked text document is modified, the extracted results of two text blocks will not match, and the authentication result of the text document will be false. The experimental results indicate that the proposed scheme is secure and efficient.