Secret key extraction with quantization randomness using Hadamard matrix on QuaDRiGa channel

Abstract

The existing scheme of secret key extraction based on the channel properties can be implemented in the three steps: quantization, information reconciliation and privacy amplification. Despite the tremendous researches of quantization and information reconciliation techniques, there is little consideration about the risk of information reconstruction by the unauthorized node due to the high correlation of subsequent quantization bits, which is unavoidably leaked on the public channel between quantization and information reconciliation. In this paper, we propose an improved scheme of secret key extraction with quantization randomness using Hadamard matrix on QuaDRiGa channel. Simulation results show that with this kind of quantization randomness, the correlation between the subsequent quantization bits can be significantly decreased, which can reduce the possibility of information reconstruction by the unauthorized node, and the improved scheme can increase the randomness of the final secret key bits as compared with the existing ones.