基于无线信道状态信息的密钥提取方案设计与实现

Design and Implementation of Key Extraction Scheme Based on Wireless Channel State Information

基于无线信道状态信息(Channel State Information, CSI)的密钥提取技术可以利用无线信道的短时互易性和时空唯一性实现合法通信双方之间的共享密钥分发,且具有计算复杂度低和无需额外设施辅助的优点,是上层加密方案的有效补充。本文分别为无线通信中的合法节点和窃听节点设计了基于CSI的密钥提取方案和被动窃听方案,并在时分双工正交频分复用通信体制下实现了所提方案的原型系统。基于实现的原型系统,本文在室内和室外两种典型通信环境中的节点静止和移动两种情况下,进行了存在窃听节点场景下的密钥提取测试实验。通过对测试结果的分析,验证了无线信道的短时互易性和时空唯一性,并表明所提密钥提取方案在典型通信场景下可以实现较高的密钥性能和系统安全性。

Since wireless channels have the characteristics of short-term reciprocity and space-time uniqueness, key extraction based on wireless channel state information(CSI) can establish shared key between legitimate communication parties. This technique is considered to be an effective complement to the upper layer encryption scheme with the advantages of low computational complexity and no need of additional facilities. In this paper, we designed a CSI-based key extraction scheme for legitimate wireless communication nodes, and a passive eavesdropping scheme for eavesdropping nodes. Furthermore, we implemented the prototype system of proposed schemes under the time division duplex orthogonal frequency division multiplexing communication system. Finally, we conducted key extraction test experiments in the presence of eavesdropping nodes under two typical communication environments(indoor and outdoor), in each of which we considered both static and mobile nodes. Analysis of test results verifies the short-term reciprocity and space-time uniqueness of the wireless channel, and shows that the proposed key extraction scheme can achieve considerable key performance and strong system security in typical communication scenarios.