Text Information Hiding Based On Modifying Font

Along with the rapid development of Internet and multimedia technologies, the information hiding technology already became a new research hot spot in information security domain. But the present research's principal aspect is aims at the covers such as images, videos ,audios to carry on the information hiding, because the text its redundant space are few, the embedding difficulty is big, therefore studies quite few, also has not formed a set of complete systems. But in fact, as an important way of the information transfers, the application fields of the texts exceed consumedly image, video and audio, occupies the key position in people's daily life. Therefore, this article has done the related research based on the text information hiding technology.This article first introduced information hiding's basic concept and the theoretical model, and introduced its characteristic, classifies and applies, as well as the information hiding technology existing question. Then has analyzed the existing text information hiding algorithm, and has realized some algorithms. On the basis of analyzing the classical micro-adjust structures of the document, word-shifting algorithm was improved, through adjusted English text's in word grouping the middle word about spacing, realized the information hideaway. The improvement algorithm does not need to choose the reference position, has realized the blind detection.Lastly, a new algorithm of information hiding based on formatted document was proposed, which was modifying fonts. This method broke through the text content and the form limit, embedded the information from Chinese character vector data's angle. Through the analysis of vector fonts' structure, the storage principle as well as the Chinese character vector data, we modified the Chinese character vector data; build a small Chinese character Font. This small font has together for the sender and receiver. Through loading the small font, the receiver reads the Chinese character vector data in the small font, and reads the corresponding character in the primitive big font, and according the embedding rules, then extracts the secret information. This method has not changed the form and the content of the text. Even the text is captured and made stegoanalysis in the form and the content, stegoanalyst is also unable to extract the embedded data. The method had advantages of large capability and good invisibility.