Information Hiding in Text Using Typesetting Tools with Stego-Encoding

A steganographic method is proposed to embed secret information into text files. This is achieved by making slight modification to scattered inter-word spaces of the formatted text using the popular typesetting tool TeX. The coded TeX file is compiled and converted to generate a stego-pdf file, which is convenient to be disseminated over the Internet. A stego-encoding technique is used to reduce the number of inter-word space changes for the same amount of embedded data so that, in comparison with a previously introduced method, the embedding efficiency is increased and security improved The embedded data are extracted from the document image that is easy to obtain from the portable pdf file