Physical Layer Secret Key Agreement Using One-Bit Quantization and Low-Density Parity-Check Codes

TL;DR

This paper introduces a novel method for physical layer secret key generation in wireless systems using one-bit quantization and LDPC codes, improving key agreement reliability.

Contribution

It proposes a new LLR calculation method based on one-bit quantization and channel estimate differences, enhancing physical layer key agreement performance.

Findings

Improved probability of bit agreement with the new LLR method

Numerical results demonstrate better performance over alternative methods

Enhanced reliability in secret key generation

Abstract

Physical layer approaches for generating secret encryption keys for wireless systems using channel information have attracted increased interest from researchers in recent years. This paper presents a new approach for calculating log-likelihood ratios (LLRs) for secret key generation that is based on one-bit quantization of channel measurements and the difference between channel estimates at legitimate reciprocal nodes. The studied secret key agreement approach, which implements advantage distillation along with information reconciliation using Slepian-Wolf low-density parity-check (LDPC) codes, is discussed and illustrated with numerical results obtained from simulations. These results show the probability of bit disagreement for keys generated using the proposed LLR calculations compared with alternative LLR calculation methods for key generation based on channel state information. The proposed LLR calculations are shown to be an improvement to the studied approach of physical layer secret key agreement.