面向物联网准静态信道的中继协作密钥生成方法

摘要

针对物联网准静态信道下密钥生成速率低的问题,该文提出一种基于中继节点协作的密钥生成方法.首先,通信双方通过信道估计获得直达信道和部分中继信道信息;然后,中继节点采用网络编码技术参与协作,使得通信双方获取全部中继信道信息;最后,通信双方在直达信道上进行密钥协商,利用直达信道信息、中继信道信息与协商信息共同生成相同的密钥.安全性分析表明该方法能够提高可达密钥速率,并且随着信噪比的提高,可达密钥速率呈线性增长,趋于最优值.蒙特卡洛仿真验证了理论分析的结果,并得出了增加中继节点数量、选取信道变化幅度大的中继节点,可以进一步提高可达密钥速率.%A secret key generation scheme based on a cooperative relay is proposed to improve the generated secret key rate for quasi-static channels in Internet of things. Firstly, the two legitimate nodes send training sequences to estimate the direct channel information, respectively. After that the relay employs network coding technique to participate the cooperation, and assists the two legitimate nodes to obtain the relay channels information. Finally, the two legitimate nodes agree on a secret key from the direct and relay channels information using the direct channel without the help of the relay. Security analysis results show that the scheme can improve the achievable secret key rate, and the achievable key rate increases linearly with SNR, approaching the optimal rate. Monte Carlo simulation verifies the security analysis results, and obtains that increasing the relay nodes, selecting the relay with a larger variance channel can further improve the achievable secret key rate.