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

Abstract

In this paper, we propose a carrier frequency offset (CFO) based key masking scheme for physical layer challenge-response authentication mechanism (PHY-CRAM) in spatially correlated channels. The estimated channel state information (CSI) and CFO between legitimate users are encapsulated with the proposed algorithm to conceal a secret key. CFO is originated from hardware imperfection which is independent on the physical location, and is cannot be forged by an adversarial user. For numerical evaluations, we assumed legitimate users and attackers in a virtual communication environment under Rayleigh fading channels. Two performance metrics are investigated by means of area under the curve of receiver operating characteristic and secret key disagreement ratio (SKDR). The results demonstrate that the proposed CFO-based PHY-CRAM shows constant SKDR regardless of the signal to noise ratio (SNR), while providing improved reliability performance compared to the conventional PHY-CRAM schemes under correlated channel environments.