A Carrier Frequency Offset based Key Masking Scheme for Physical-Layer Authentication in Spatially Correlated Channels

Abstract

In this paper, we propose a key masking scheme using carrier frequency offsets for physical-layer challenge-response authentication mechanism (C-PHY-CRAM) which prevents eavesdropper from exploiting a secret key with correlated channels in multicarrier systems. In the conventional PHY-CRAM method, if an eavesdropper is close to a legitimate user, a secret key can be exposed to the eavesdropper since two channels to mask the secret key can be strongly correlated. To avoid the potential leakage of the key, CFO induced by the local oscillator difference between transceivers is employed as an extra attribute to encapsulate a secret key in the proposed C-PHY-CRAM. Through channel simulations, we demonstrate that the proposed scheme outperforms conventional PHY-CRAM and its alternative for correlated channel environments.