Title: The Passive Eavesdropper Affects my Channel: Secret-Key Rates under Real-World Conditions (Extended Version),
Abstract: Channel-reciprocity based key generation (CRKG) has gained significant
importance as it has recently been proposed as a potential lightweight security
solution for IoT devices. However, the impact of the attacker's position in
close range has only rarely been evaluated in practice, posing an open research
problem about the security of real-world realizations. Furthermore, this would
further bridge the gap between theoretical channel models and their
practice-oriented realizations. For security metrics, we utilize
cross-correlation, mutual information, and a lower bound on secret-key
capacity. We design a practical setup of three parties such that the channel
statistics, although based on joint randomness, are always reproducible. We run
experiments to obtain channel states and evaluate the aforementioned metrics
for the impact of an attacker depending on his position. It turns out the
attacker himself affects the outcome, which has not been adequately regarded
yet in standard channel models.