Non Intrusive Wi-Pi CSI Obfuscation Against Active Localization Attacks

Abstract

Channel State Information (CSI) based localization with 802.11 has been proven feasible in multiple scenarios and is becoming a serious threat to people privacy in work spaces, at home, and maybe even outdoors, even if outdoors experiments proving the feasibility are still not available. Countering unauthorized localization without hampering communications is a nontrivial task, although some very recent works suggest that it is feasible with marginal modification of the 802.11 transmission chain, but this requires modifying 802.11 devices. Furthermore, if the attacker controls two devices and not only a receiver, transmission side signal manipulation cannot help. This work explores the possibility of countering CSI based localization with an active device that, instead of jamming signals to avoid that a malicious receiver exploits CSI information to locate a person, superimpose on frames a copy of the same frame signal whose goal is not destroying reception as in jamming, but only obfuscate the location relevant information carried by the CSI. A prototype implementation and early results looks promising; they show feasibility of location obfuscation with high efficiency and excellent preservation of communication performance, paving the road for further research and improved users privacy.