Speech scrambling based on chaotic maps and one time pad

This paper presents a chaos-based speech scrambling system. Chaotic maps have been successfully used for large-scale data encryption such as image, audio and video data, due to their good properties such as pseudo-randomness, sensitivity to changes in initial conditions and system parameters and aperiodicity. This paper uses two chaotic maps, circle map and logistic map for speech confusion and diffusion, respectively. In the confusion stage, speech samples are divided into small segments. Then, indices of ordered generated sequence of circle map are used to shuffle the positions of the speech signal segments. Then, a one-time pad generated by the logistic map is used for the diffusion stage. Several experimental results, signal-to-noise ratio, key space, key sensitivity tests, statistical analysis, chosen/known plaintext attack and time analysis show that the proposed method for speech scrambling performs efficiently and can be applied for secure real time speech communications.