Wireless physical layer key generation with improved bit disagreement for the internet of things using moving window averaging

Abstract

Achieving information security in the Internet of things (IoT) by means of physical layer key generation is an open research area. In the key generation, the secret key is generated using the physical (PHY) layer characteristics of the communication channel as a source of randomness. IoT networks are characterized as noisy & heterogeneous networks with lower transmission power. In this paper, we propose a wireless secret key generation approach by pre-processing the received signal strength indicator (RSSI) of beacons exchanged between Alice and Bob using moving window averaging (MWA). Our proposed approach has significant improvement in performance, at lower SNR range. The size of the moving window is selected on the basis of improvement in the standard deviation of the RSSI pattern. It is also suggested to quantize the pre-processed RSS samples through Lloyd–Max based quantizer to minimize quantization error, which further improves bit disagreement (BDR). It is clear from results that the proposed approach has considerable improvement in bit disagreement rate (BDR) at low SNR by applying the selected window size. The performance of the proposed approach is also evaluated by performing randomness testing of the generated keys using National Institute of Standards and Technology (NIST) test set for randomness.