Key dependent covert communication system for audio signals

Acoustic signals such as speech and music are commonly used in our day to day life. In recent years, the framework for hiding data into digital audio signals has received extensive research consideration. In this paper, we present a novel mechanism for effective encoding and decoding of hidden data into audio signal´s transformed coefficients by decomposing them into Fibonacci bit-lines. Fibonacci bit-lines offer more potential space for data-hiding (since the number of Fibonacci bit-lines is higher than the traditional bit-lines). The proposed technique aims at: i) improving the capacity of the system; ii) improving the stego imperceptiveness; iii) selecting the best audio signal for hiding data from a class of signals; and iv) establishing a covert communication over a public audio channel. The embedded information could be retrieved without prior knowledge of the cover signal. The simulation results were performed over 25 various acoustic signals. In addition, future enhancements of the proposed system are discussed.