Golay Code Based Bit Mismatch Mitigation for Wireless Channel Impulse Response Based Secrecy Generation

Abstract

The wireless radio communications channel between two legitimate user terminals has long been considered as a renewable source of shared secrecy. As characterization of the channel, the time-varying channel impulse response (CIR) is commonly used for this purpose due to its reciprocity and inherent difficulty in being captured by an adversary. While each terminal generates a secret key at its side, based on its own channel measurements combined with an independent noise component, mismatches may occur in the extracted information or in the obtained bit sequences after a sampling and quantization process. To mitigate such bit mismatches, we propose a method that utilizes the properties of the Golay code to correct or detect the bit mismatches for CIR-based secret key agreement. In our approach, the reconciliation information in the transmission is deliberately designed to hide the original shared information (perfect or imperfect). The correctness of our bit mismatch mitigation algorithm is thoroughly analyzed for all possible scenarios. In addition, the effectiveness of our algorithm is validated through simulations using MATLAB for generated CIR data, the results of which match our theoretical analysis. Our design is shown to be secure and optimal by security analysis and comparisons between our proposed algorithm and its variants. The comparisons with related techniques and the scenarios in which our design can benefit are also discussed.