WiCloak: Protect Location Privacy of WiFi Devices

The rapid development of WiFi localization poses a serious privacy threat, as eavesdroppers can locate WiFi devices without their consent. In this paper, we present WiCloak, the first system that protects WiFi device location privacy while supporting normal WiFi communication simultaneously. The high-level idea of WiCloak is to inject a fake channel into WiFi CSI at the transmitter, which renders the CIR and time information obtained by eavesdroppers meaningless. We mathematically prove that the injected fake channel is effective in any wireless environment and can strictly protect the location privacy of WiFi devices. To simultaneously support communication for commercial WiFi receivers, we propose a method to cancel out the fake channel impacts in decoding and prove that the method should not impact communication performance. WiCloak can work on commercial WiFi devices without any hardware modification. We evaluate the communication performance of WiCloak on commercial WiFi receivers (e.g., MacBook and Mac Studio) and demonstrate that it achieves the same packet reception rate as normal WiFi. We show that WiCloak increases the localization error by 22× to normal WiFi.