Unconditionally secure communications over fading channels

In this paper, we propose a novel method for two communicates to exchange a secret over a public wireless fading channel. Unlike conventional computationally secure public key methods, this technique is information theoretic and unconditionally secure provided that a component of the reciprocal channel fading over time between the two communicates is statistically independent with the channel fading from either communicate to the eavesdropper. This technique may be particularly well suited to secure tactical mobile communications. A simple protocol suitable for a lognormal shadowed fading channel is described and its key exchange rate is derived.