iJam with channel randomization
iJam with channel randomization
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DOI：
10.1145/3395351.3401705
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发表时间：
2020-07
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通讯作者：
Jordan L. Melcher;Yao Zheng;Dylan Anthony;Matthew Troglia;Yanjun Pan;Ming Li;Thomas Yang;Alvin Yang;Samson Aggelopoulos
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文献类型：
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作者：
Jordan L. Melcher;Yao Zheng;Dylan Anthony;Matthew Troglia;Yanjun Pan;Ming Li;Thomas Yang;Alvin Yang;Samson Aggelopoulos
物理层密钥生成方法利用通信信道的变化在没有事先安全关联的情况下实现两方之间的安全密钥协商。它们的保密率（比特生成率）在很大程度上取决于信道的随机性，在稳定的环境中可能会显着降低。现有方法试图通过向信道中注入人工噪声来提高保密率。不幸的是，噪声注入无法改变底层的信道状态，这取决于发送器和接收器之间的多径环境。因此，已知这些方法会向多天线窃听者泄露密钥，而多天线窃听者能够通过多个信号接收的差分来过滤噪声。这项工作展示了一种增强物理层密钥生成方案（例如通道随机化）的改进方法。信道随机化方法利用可重构天线在传输过程中快速改变信道状态，并利用基于出发角 (AoD) 的信道估计算法来消除对预期接收器的变化影响。综合结果是通信信道在预期接收者眼中是稳定的，但从窃听者的角度来看是随机变化的。我们用所提出的方法增强了现有的物理层密钥生成协议 iJam，并开发了一个成熟的远程仪器平台来展示其性能。我们的评估表明，增强不会影响密钥建立期间预期接收器的误码率 (BER)，但会将窃听者的 BER 降低到随机猜测的水平，无论其配备的天线数量如何。
Physical-layer key generation methods utilize the variations of the communication channel to achieve a secure key agreement between two parties with no prior security association. Their secrecy rate (bit generation rate) depends heavily on the randomness of the channel, which may reduce significantly in a stable environment. Existing methods seek to improve the secrecy rate by injecting artificial noise into the channel. Unfortunately, noise injection cannot alter the underlying channel state, which depends on the multipath environment between the transmitter and receiver. Consequently, these methods are known to leak key bits toward multi-antenna eavesdroppers, which is capable of filtering the noise through the differential of multiple signal receptions. This work demonstrates an improved approach to reinforce physical-layer key generation schemes, e.g., channel randomization. The channel randomization approach leverages a reconfigurable antenna to rapidly change the channel state during transmission, and an angle-of-departure (AoD) based channel estimation algorithm to cancel the changing effects for the intended receiver. The combined result is a communication channel stable in the eyes of the intended receiver but randomly changing from the viewpoint of the eavesdropper. We augmented an existing physical-layer key generation protocol, iJam, with the proposed approach and developed a full-fledged remote instrumentation platform to demonstrate its performance. Our evaluations show that augmentation does not affect the bit error rate (BER) of the intended receiver during key establishment but reduces the eavesdropper's BER to the level of random guessing, regardless of the number of antennas it equips.