Component-based digital watermarking of Chinese texts

摘要

According to the types of the host media, digital watermarking may be classified mainly as image watermarking, video watermarking, audio watermarking, and text watermarking. The principle of the three watermarking research fields are similar in that they make use of the redundant information of their host media and the characteristics of human video system or human audio system. Unfortunately, text has no redundant information. Text watermarking techniques are totally different from them. And text watermarking algorithm is very difficult to satisfy the requirements of transparence and robustness. In this paper, a novel text watermarking algorithm based on the thought of the mathematical expression will be presented. Since watermarking signals are embedded into some Chinese characters that can be divided into left and right components, this algorithm is totally based on the content. Therefore, it breaks through the difficulties of text watermarking. Experiments also show that the component-based text watermarking technique is relatively robust and transparent. It will play an important role in protecting the security of Chinese documents over Internet.