Practical Provably Secure Communication for Half-Duplex Radios

In this paper, we present a practical and provably secure two-way wireless communication scheme in the presence of a passive eavesdropper. The scheme implements a randomized scheduling and power allocation mechanism, where each legitimate node transmits in random time slots and with random transmit power. Such randomization results in ambiguity at the eavesdropper with regard to the origin of each transmitted frame. The scheme is analyzed in a time-varying binary block erasure channel model and secrecy outage probabilities are derived and empirically evaluated. The scheme is implemented over an IEEE 802.15.4-enabled Sun SPOT sensor motes. The results show that the proposed scheme achieves significant secrecy gains with a vanishing outage probability, at the expense of slight decrease in throughput, even when the eavesdropper is equipped with a receive power based classifier and is located too close to the transmitter node.