A novel information hiding scheme based on social networking site viewers' public comments.

In earlier reported chat-based steganography techniques, only direct communication between the sender and receiver was considered which can raise suspicion for further investigations by an attacker. If the adversary traces the communication between the two, he may investigate to find out the data shared during communication, can alter the content, or destroy it. In such a situation, a steganography system is required which can bypass adverse attention through indirect communication instead of direct communication. In this paper, we propose a new framework to camouflage hidden communication between the transceivers. The framework is based on online social networking and video-sharing website's communication. The secret message is communicated using comment features of these social networking and video-sharing websites in a totally new way compared with earlier approaches. Stego-comment is generated by performing synonym-substitution based on Huffman code on the auto-summarized previous comments of a chosen post. The stego-comment does not raise any suspicion to the intermediary by being technically similar to other comments which may not have any hidden message, which makes this method successful. Similarity indices of the stego-comment with respect to other comments are calculated using a String Similarity Tool which uses fuzzy comparison functions between strings for one sample dataset. The proposed method gives average bit-rate (as a measure of embedding efficiency) of 9.04 bits per sentence for a set of five different case studies which is high compared with average bit rates found in the literature. This communication cannot be traced between the communicators through traffic analysis in any easy way due to the absence of any direct communication. [ABSTRACT FROM AUTHOR]