Recent Trends in Text Steganography with Experimental Study

Abstract

There have been pressing needs for securing a document and its content, either in electronic form or printed form. This is because counterfeiting and forgeries are extremely widespread all over the world, causing tremendous damage to individuals, industries, societies, and even national security. This is the main reason why people think about to protect their work and prevent such illicit activities. Because of these various methods like cryptography, steganography, and coding have been used. Steganography is the best-suited technique that allows user to hide a message in another message (cover media). Most of steganography research uses cover media as pictures, video clips, and sounds. However, text steganography is not normally preferred due to the difficulty in finding redundant bits in text document. To embed information inside a document, its characteristics have to be altered. These characteristics can be either insertion of spaces or non-displayed characters, deliberate misspellings distributed throughout the text, resizing of fonts, and so on. But due to slight change in the document it will be visible to the third party or attacker. To overcome this problem there is a need to alter the document in such a way that it will not visible to the human eyes yet it is possible to decode it with computer. The present chapter highlights the technique for reconstruction of the printed document using text-based steganography. This technique may be used if the original document (e.g., bank checks, legal documents, and certificates) is torn out and the important information is lost. Extracting the information from the torn part of the document and recreating the document will help in regaining the lost information. This method will first extract the text information present in the document and encode it into symbols. Then embed these symbols into the document multiple numbers of times without affecting the integrity of the document. For recreating the document, the hard copy of the document can be processed in order to retrieve the embedded information. Thus, the information is regained from the original printed text document. This method will help in reconstruction of printed document from its part or whole.