Wireless radio channels are known to contain information about the surrounding propagation environment, which can be extracted using established wireless sensing methods. Thus, today's ubiquitous wireless devices are attractive targets for passive eavesdroppers to launch reconnaissance attacks. In particular, by overhearing standard communication signals, eavesdroppers obtain estimations of wireless channels which can give away sensitive information about indoor environments. For instance, by applying simple statistical methods, adversaries can infer human motion from wireless channel observations, allowing to remotely monitor premises of victims. In this work, building on the advent of intelligent reflecting surfaces (IRSs), we propose IRShield as a novel countermeasure against adversarial wireless sensing. IRShield is designed as a plug-and-play privacy-preserving extension to existing wireless networks. At the core of IRShield, we design an IRS configuration algorithm to obfuscate wireless channels. We validate the effectiveness with extensive experimental evaluations. In a state-of-the-art human motion detection attack using off-the-shelf Wi-Fi devices, IRShield lowered detection rates to 5% or less.
翻译:已知无线无线电频道包含关于周围传播环境的信息,这种信息可以通过既有的无线遥感方法提取。因此,今天无处不在的无线装置是被动窃听者发动侦察攻击的诱人目标。特别是,通过偷听标准的通信信号,窃听者获得无线频道的估计,这种无线频道能够提供关于室内环境的敏感信息。例如,通过应用简单的统计方法,对手可以从无线频道观测中推断出人类运动,允许远程监测受害人的场所。在这项工作中,在智能反射表面的出现的基础上,我们建议使用IRShield作为对抗对抗对抗对抗性无线感测的新型反措施。IRShield是设计为现有无线网络的插和播放隐私延伸。在IRShield的核心,我们设计了一套IRS配置算法,以模糊无线频道。我们用广泛的实验性评估来验证其有效性。在使用离子W-Fi设备进行的最新人类运动探测攻击中,IRShield将探测率降低到5%或更低5%。