Plausible Deniability Using Automated Linguistic Stegonagraphy

Information hiding has several applications, one of which is to hide the use of cryptography. The Nicetext [5, 6] system introduced a method for hiding cryptographic information by converting cryptographic strings (random-looking) into “nice text” (namely innocuous looking). The system retains the ability to recover the original ciphertext from the generated text. Nicetext can hide both plaintext and cryptographic text. The purpose of such transformations are to mask ciphertext from anyone who wants to detect or censor encrypted communication, such as a corporation that may monitor, or censor, its employee private mail. Even if the message is identified as the output of Nicetext, the sender might claim that the input was simply a pseudo-random number source rather than ciphertext. This paper extends the Nicetext protocol to enable deniable cryptography/messaging using the concepts of plausible deniability [2, 7]. Deniability is derived from the fact that even if one is forced to reveal a key to the random string that “nice text” reverts to, the real cryptographic/plaintext messages may be stored within additional required sources of “randomness” in the extended protocol.