基于多随机信号流的密钥生成方案  

Secret Key Generation Method Based on Multi-stream Random Signal

作　　者：金梁[1] 蔡奥林 黄开枝[1] 钟州[1] 楼洋明[1] JIN Liang;CAI Aolin;HUANG Kaizhi;ZHONG Zhou;LOU Yangming(National Digital Switching System Engineering & Technological Research Center, Zhengzhou 450002, China)

机构地区：[1]国家数字交换系统工程技术研究中心

出　　处：《电子与信息学报》2019年第6期1405-1412,共8页Journal of Electronics & Information Technology

基　　金：国家重点研发计划(2017YFB0801903);国家自然科学基金(61601514,61501516,61521003,61471396)~~

摘　　要：基于随机信号流的密钥生成方案会在合法发送方发送随机信号时泄露部分共享随机源信息导致密钥安全性和可达密钥速率较低。针对此问题,该文提出一种基于多随机信号流的密钥生成方案。首先,发送方利用信道互易性和上行导频估计下行信道,然后发送方在各天线上发送相互独立的随机信号流。由于窃听者难以准确估计所有随机信号流,因此难以窃取接收方每根天线接收到的叠加随机信号,而发送方则可根据估计的下行信道和自身发送的随机信号流计算出接收方各天线的接收信号。因此,可以将接收天线上的叠加随机信号作为共享随机源提取密钥。进一步地,该文还推导了该方案的可达密钥速率和共享随机源的互信息量表达式,并分析了两者间的关系以及对密钥安全性的影响。最后,通过仿真验证了该方案的有效性,仿真结果表明该方案能够有效降低窃听者观察到的共享随机源互信息,从而提升可达密钥速率及密钥安全性。The secret key generation method based on random signal may leak part of the common randomness information and reduce the achievable secret key rate when legal transmitter transmits random signal. In response to this problem, the secret key generation method based on multi-stream random signal is proposed. Firstly, the transmitter uses the channel reciprocity and uplink pilot to estimate the downlink channel, then the transmitter transmits mutually independent signal on every antenna. The eavesdropper is difficult to estimate all the random signals. It is difficult to estimate all the random signals for the eavesdropper, so the overlapping signal received by every antenna is difficult to be obtained by the eavesdropper. However, the legal transmitter is able to calculate the signal received by legal receiver by using the downlink channel estimated and the signal transmitted. So, the overlapping signal on every legal antenna can be used to extract secret key as common randomness. Also, the achievable secret key rate expression and the mutual information expression of common randomness are derived, and the relationship between them and the secret key security is analyzed. At last, the effectiveness of this method is verified by the simulation. The simulation results show that this method can reduce the common randomness observed by the eavesdropper to raise the achievable secret key rate and secret key security.

关 键 词：物理层安全 多随机信号流 密钥生成 可达密钥速率 

分 类 号：TN92[电子电信—通信与信息系统]