Research On Text Digital Watermarking Technology Based On Hamming Code

With the rapid development of Internet technology and the rapid spread of personal computer and smartphone, in the multimedia carrier, information transmission, exchange and getting have become more and more convenient and quick, but at the same time, they produce a series of new important problems and challenges.To solve the problem of copyright theft,digital watermarking technology appeared.Some identifying information are embedded in a multimedia carrier to protect copyright. Little redundancy of adding the marking stations in the text document is the reason of little researching. Using the principle and composition of hamming codes, adding spaces, synonym substitution algorithm and matrix encoding, this paper explore a robust digital watermarking algorithm and a reversible text digital watermarking algorithm. The embody investigation works as follows:(1) Combining these different watermarking methods, the paper presents a text watermarking algorithm based on synonym substitution algorithm and adding spaces encoding. The algorithm first use the hamming code to encode the watermarking information,and then embeds the two parts of the hamming code of the watermarking information in various ways, embedding the parity bits into the text by inserting spaces with matrix coding and embedding the information codes into the text by using ordinary synonym substitution algorithm. The experimental results indicate that this algorithm not only enjoys good invisibility but also has good robustness towards routine attacks, especially resist the attacks of text semantic content.(2) Using the features of hamming code, the paper figured out a novel text reversible digital watermarking algorithm. The algorithm first preprocesses the original text, using the hamming code to encode the coded values of the original grouped replaceable synonyms,which are regarded as the data bits, and then embeds the obtained parity bits into the text by inserting spaces with matrix coding. Finally, selects a synonym to be replaced to embed the watermarking information according to the codes of the locations of the changed synonyms in a group. During the extraction, in terms of the decoding theory of hamming code and the rule of encoding the location of the changed synonyms in a group, the watermarking information is extracted and the original text will be restored near-losslessly. The experimental resultsindicate that this algorithm not only can recover the original text completely, but also can achieve good invisibility. Therefore, the watermarking proposed scheme has improved practical ability.