PHYSICAL LAYER SECURITY FOR WIRELESS NETWORKS BASED ON COSET CONVOLUTIONAL CODING

Abstract

This paper presents a new physical layer security for wireless networks using non-linear convolutional cryptosystem. Relevant performance metrics such as secret channel capacity and throughput are considered in the implementation. Secret channel capacity is implemented using confusion bits generated from coset convolutional coding while throughput is enhanced due to the forward error correction capability of convolutional codes. The paper establishes a method to determine wireless channel parameters for secure communication.It is shown that, the probability of correct decision of an eavesdropper is zero when appropriate values of M-PAM constellations, the number of transmitted bits, k and the signal-to-noise ratio (SNR) per bit in dB are chosen. In addition, it is shown that, the convolutional cryptosystem enhances security for the case where the eavesdropper probability of correct decision is not zero. The entire scheme applied to CDMA is ported to a Virtex 5 FPGA chip to circumvent poor key management due to additional keys used in the convolutional cryptosystem.