应用TeX控制功能和图像检测的文本密写

提出一种利用排版工具TeX在文本文件中实现密写的方法。该方法属于“文本-图像”方式,在TeX源文件中修改TeX命令,对一部分单词间空格进行微小的改变,从而将数据嵌入。经编译和转换,生成含隐蔽信息的pdf文件在互联网上传输。隐蔽信息的提取在图像域中进行,根据水平和垂直投影分别检测文字的行和单词之间的空格,恢复出原嵌入数据。密写的安全性取决于从图像中准确检测空格微小差异的能力、文本文件相对于嵌入数据量的大小、采用的加密和编码技术等因素。

Data Hiding in Text File Using TeX and Extraction of Hidden Data from Document Image

A steganographic technique using pdf files to carry secret data is proposed. Data arc embedded into the sequences in a TeX source file to slightly modify inter-word spaces in the text. Appropriate coding schemes control may be applied. The coded TeX file is then compiled and converted to generate a stego-pdf file, which is convenient to be disseminated over the Internet. In reception, jpg images arc obtained from the pdf document, and the hidden data are extracted by detecting the spaces between words. Data security is determined by the ability of reliably detecting small difference in space widths, size of the document file in terms of the amount of data to be embedded, and the encryption and coding techniques used.