Embedding and Extraction Method of Digital Watermark in Text Document

Abstract

The invention provides a text document digital watermark embedding and extracting method. According to the invention, the watermark embedding is characterized in that raw information is made into a binary image; matlab and other programming softwares are adopted for reading out binary matrixes in one-to-one correspondence with the binary image to serve as the watermark information; '0' and '1', the two binary code characters, are written into a font object library with a TrueType coinage program to generate a secret key; a windows 'internal code' input method is adopted to call binary code characters, and the binary matrix is inserted into the text document; finally a hidden text function of word processing software is adopted for hiding the imbedded binary matrix, so that the watermark embedding is completed. According to the invention, through raw information conversion and application of the secret key, the raw information is better hidden; meanwhile, due to hiding of the watermark information, an interpolator can not easily find the watermark, so that the preventive performance is improved. Therefore, the security of the raw information is greatly enhanced.

Description

Technical field [0001] The invention relates to a method for embedding and extracting a digital watermark, in particular to a method for embedding and extracting a digital watermark for a text document. It is mainly used for copyright protection, tamper-proofing, and confidential communication of text documents. Background technique [0002] In the prior art, Chinese patent 201110396024.X provides "a method for secure communication using word documents", in which the first step of watermark embedding is to write the original information as watermark information into the font library of the TrueType word-making program, and generate Key; the second step is to embed the watermark information in the word document, and then stack each watermark character in the watermark information on the normal characters. The patent sets up two lines of defense for watermark information: the first is the key, that is, as long as the key is not obtained, the watermark characters cannot be displaye...

AI Technical Summary

Problems solved by technology

The patent sets up two lines of defense for watermark information: the first is the key, that is, as long as the key is not obtained, the watermark characters cannot be displayed, which plays a decisive role in preventing crime; the second is the stacking of characters, which is also That is to say, even if you get the key and display the watermark characters, what you see is the situation where the watermark characters and normal characters are stacked together, which is difficult to identify, thus creating another obstacle for extracting the original information

[0003] The disadvantage of the above-mentioned patent is that although it has two lines of defense, it is actually only one line of defense for the key. Anti-crime function, because once the key is compromised, you can directly see the existence of the "watermark character" when you open the document, and the unfolding of the stack is realized in this word processing software, so it is easy to unfold it

Furthermore, due to the stacking of fonts, there will be abnormal operations such as "difficult to delete" or "insert" during editing, which makes it easy for the intruder to detect the existence of "watermark", thereby reducing the security; at the same time, The watermark information is the original information, and the original information can be seen directly as long as the stack is unfolded, so the confidentiality is not high enough

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