Impact of Realistic Propagation Conditions on Reciprocity-Based Secret-Key Capacity

Rottenberg, François [UCL] De Doncker, Philippe Horlin, Francois Louveaux, Jérôme [UCL]

Secret-key generation exploiting the channel reciprocity between two legitimate parties is an interesting alternative solution to cryptographic primitives for key distribution in wireless systems as it does not rely on an access infrastructure and provides information-theoretic security. Many works in the literature assume that the eavesdropper gets no side information about the key from her observations provided that: (i) it is spaced more than a wavelength away from a legitimate party and (ii) the channel is rich enough in scattering. In this paper, we show that this condition is not always verified under realistic propagation conditions and we study the resulting secret-key capacity.