The Research On Text Digital Watermarking Based On Chinese Mathematical Expressions

The research of the text digital watermarking is a cross research field. It involves researches of cryptography, Chinese information processing, image processing, graphics, science of vision, communication and the information security, etc. It is such a new field in theory, that the research methods abroad are very single and domestic report about this research is very few. There are lots of theoretical problems worthy to be researched thoroughly. Currently, the text digital watermarking researches usually have bad robustness and poor invisibility at home and abroad, because the codes of the characters forming the text have special standards of nations and international, as soon as the code being changed, the characters will be changed correspondingly. Therefore, it is very difficult to research a robust text digital watermarking algorithm.The Chinese mathematical expression theory can remedy the inadequacy of information of a Chinese character ISN(internal statement number), which ensuring that a computer handles Chinese characters in Chinese components whose granularity is much smaller than Chinese characters. In order to solve the defect of bad robustness and poor invisibility of the text digital watermarking, this paper makes a thorough research of the text digital watermarking based on the Chinese mathematical expression theory.For preparing for the researches of text digital watermarking and advantaging other researchers' development when using the Chinese mathematical expression theory, this paper designs and realizes a development platform of Chinese mathematical expression. It has been proved by experiments that the platform's function, execution speed and stability can satisfy the requirements of conversion and operation of enormous data.This research found out that the structure information of Chinese have plenty redundant information that can be used by the Chinese mathematical expression for the digital watermarking, the data embedded can possess better robustness. Based on this finding, this paper designs a kind of text digital watermarking method of embedding watermarking by using Chinese structure, and realizes the method by using the Chinese mathematical expression platform.Considering the watermarking embedding algorithm's importance to the robustness of the text digital watermarking, this paper makes fully use of the advantage of the Chinese mathematical expression theory to design a kind of layered text method, which has being realized by using the Chinese mathematical expression platform. The layered text method can handle the text as a solid structure, and the embedding data havepreferable robustness.Finally, based on the researches of the text digital watermarking method and the text layered method, this paper integrates the method of making use of the Chinese structure embedding watermarking with the robust algorithm based on text layered, and realizes a brand-new text digital watermarking method. Proved by lots of experiments, this brand-new method has good robustness and better invisibility.