WiShield: Fine-grained Countermeasure Against Malicious Wi-Fi Sensing in Smart Home
Yihui Yan, Zhice Yang · 2024
Wi-Fi sensing technology can infer information about the environment, including user privacy. With the evolution of the smart home, more and more Wi-Fi devices are placed in a home. The ubiquitous Wi-Fi devices lead to concerns over privacy breaches caused by Wi-Fi sensing. In this paper, we discuss the insider threat model, where the smart device may be used to spy on the user through Wi-Fi sensing. To protect user privacy in the insider model, we propose WiShield, a bolt-on countermeasure against abusing smart devices for malicious Wi-Fi sensing in a per-device manner. WiShield works by attaching it to the smart devices. It utilizes low-cost radio frequency (RF) components to obfuscate the smart devices’ sensing by switching among multiple propagation paths with different gains and lengths. The user can recover a certain device’s sensing by disabling the corresponding WiShield through a policy configuration or command. We validate the effectiveness of WiShield against two state-of-the-art sensing strategies. The result shows that WiShield is effective in hiding most information contained in the Wi-Fi signals.