A Survey on Text Based Steganography

In a modern era of Information Technology, illicit copying and illegal distribution accompany the adoption of widespread electronic distribution of copyrighted material. This is the main reason why people think about how to protect their work and how to prevent such unlawful activities. For this purpose various methods including cryptography, steganography, coding and so on have been used. Steganography is the bestsuited technique that allow 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 should be altered. These characteristics can be either the text format or characteristics of the character. But the problem is that if slight change has been done to the document then it will become visible to the third party or attacker. The key to this problem is that to alter the document in such a way that it is simply not visible to the human eye yet it is possible to decode it with computer. For this purpose various methods of text-based steganography have been purposed like line shifting, word shifting, feature coding, white space manipulation etc. In this paper, we present an overview of the steganography, with a particular focus on textbased steganography in details.