不同环境下无线信道密钥生成性能研究

在无线通信物理层安全的研究中,通信双方的信道具有很好的短时互易性,可以从无线信道中提取出相似的信道特征并生成一致的密钥.该技术可以利用无线信道天然的随机性为无线通信系统实时的分配对称密钥.本文利用通用软件无线电平台(USRP)设计并实现了实时的无线信道密钥生成系统.基于设计的无线密钥生成系统,本文在室内房间、室内走廊、空旷室外三种不同场景中的终端固定、终端移动以及人员走动三种不同信道环境下长时间测量了无线信道并生成了密钥.通过分析合法通信双方和窃听者信道状态信息(CSI)的互易性、CSI信息泄露率、CSI随机性、密钥随机性四个指标,详细分析了不同场景及环境下无线信道密钥生成技术的安全性与可靠性.通过实验表明,空旷室外信道随机性最高,室内走廊随机性其次,室内房间随机性最低.此外,周围环境变化愈快,信道随机性愈高.通过选择合适的密钥生成参数,都可以在不同的场景及环境下生成满足随机性要求的密钥.

On Key Generation Performance of Wireless Channel in Different Environments

In physical layer security of wireless communication, both sides’ communication channel has good short-term reciprocity. Similar channel characteristics and a pair of consistent key can be extracted from a wireless channel. The technique can utilize the randomness of the wireless channel to assign a symmetric key for the wireless communication system in real time. This paper designs a realtime wireless channel key generation scheme using the universal software radio platform(USRP). Based on this scheme, this paper measures the wireless channel and generates a key for a long time under three channel environments(terminal fixation, terminal movement and personal walking) in three scenes(indoor room, indoor corridor, outdoor space). This paper calculates reciprocity of channel state information(CSI), CSI Information leakage rate, CSI randomness and key randomness. The security and reliability of the wireless channel key generation technology are analyzed in different scenes. Experiments show that the channel randomness of outdoor space is the highest among all scenes, that of indoor corridor is the second and that of indoor room is the lowest. In addition, the faster the surrounding environments changes, the higher the channel randomness will be. This system can generate the enough random keys in different scenes and environments by setting appropriate system parameters.