Edinburgh Napier University

  Secure communication has always been a demanding area in civil, commercial and particularly in military set up. Robust and time-tested efficient algorithms are needed to have an essential privacy for speech transmission in the telephone networks, radio communication and in the emerging cellular mobile radio systems. In this paper, we present a highly secure speech encryption algorithm based on amplitude scrambling and Discrete Cosine Transform (DCT) coefficients scrambling. The permutation is performed using TD-ERCS chaotic map. The proposed scheme has been implemented successfully on software framework which yielded zero residual intelligibility and high quality of recovered speech. Simulation results reveal that the anticipated algorithm is secure enough and resistant against various security attacks. The authors are reasonably confident of their contribution which can eventually be exploited as software, hardware-software and an integral part of any embedded secure communication system.