ReLACK: A Reliable VoIP Steganography Approach

VoIP steganography is a real-time network steganography, which utilizes VoIP protocols and traffic as a covert channel to conceal secret messages. Recently, there has been a noticeable increase in the interest in VoIP steganography due to the volume of VoIP traffic generated, which proved to be economically feasible to utilize. This paper discusses VoIP steganography challenges, compares the existing mechanisms, and proposes a new VoIP steganography approach. Current VoIP steganography techniques lack mechanisms to provide reliability without weakening the steganography system. Accordingly, this paper modifies the (k, n) threshold secret sharing scheme, which is based on Lagrange's Interpolation, and then applies a two phase approach on the LACK steganography mechanism to provide reliability and fault tolerance and to increase steganalysis complexity. The cost of reliability is a loss in bandwidth, therefore, the proposed approach also provides mechanisms to maximize packets utilization to mitigate the effect of adding redundancy.