【作者】 严智萍；

【导师】 朱更明；

【作者基本信息】 湖南科技大学 ， 计算机应用技术， 2008， 硕士

【摘要】 随着因特网和多媒体技术的的迅猛发展,信息隐藏技术已经成为信息安全领域一个新的研究热点。而目前研究的主要方面是针对图像、视频、音频等载体来进行信息隐藏,文本由于其冗余空间少,隐藏难度大,因此研究得比较少,也没有形成一套完整的体系。而事实上,文本作为信息传递的一种手段,其应用大大超过了图像、视频等范围,在人们的日常生活中占据重要位置。因此,本文就基于文本的信息隐藏技术做了相关研究。本文首先介绍了信息隐藏的基本概念和理论模型,并介绍了其特点、分类和应用、以及信息隐藏技术存在的问题。然后分析了现有的格式文本的信息隐藏算法,并实现了其中的一些算法。在分析了传统的文档结构微调法的基础上,对字移编码方法进行了改进,通过将英文文本中的单词分组来调整中间单词的左右间距,来实现信息的隐藏。改进的算法不需要选择参考位置,实现了盲检测。最后,提出了一种新的基于格式文档的信息隐藏算法——基于修改字库的信息隐藏。该方法突破了文本的内容和格式的限制,从汉字的矢量数据的角度出发来进行信息隐藏。通过分析矢量字库的结构、存储原理以及汉字的矢量数据,我们对汉字的矢量数据进行修改,来建立一个小汉字库,这个小字库供发送方和接收方共同持有。接收方通过装载这个小字库,读取小字库中汉字的矢量数据,并读取原始大字库中对应汉字的矢量数据,对照嵌入规则,即可提取出秘密的信息。该方法没有改变原始文本载体的格式和内容,即使伪装分析者截获了载体文本,对其做格式上和内容上的分析也无法提取出隐藏的信息。该方法具有隐藏容量大和隐蔽性强的特点。更多还原

【Abstract】 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.更多还原