Text based steganography

Abstract

Steganography is the art of hiding information within other less conspicuous information to prevent eavesdropping by way of hiding its existence in the first place. Image based steganography is the most common form but text based steganography can also be used. Text based steganography can be generally classified as format based, linguistic and random/statistical generation. In general, random and statistical generated methods create a cover text but do not necessarily make semantic sense; that is, the subject matter of each sentence has little or no relation to the next sentence. Linguistic steganography can use natural language processing to hide information but again is still subject to analysis particularly if the basis for the cover text is an existing document. Here, we examine the leading methods of text based steganography. We evaluate a variety of steganographic techniques including open space encoding, synonym replacement, UK/US English translation algorithm and Wayner's Mimic Functions using five benchmarks which compare speed, capacity, complexity, compromisability and size. We find that the best methods to hide information should not use a single scheme, but a hybrid of many schemes. In order to further hide information, text should be compressed, encrypted and then hidden in a cover document.