Design privacy-preserving cross-protocol countermeasures without sacrificing utility

Design countermeasures that provide strong privacy against cross-protocol tracking while preserving the utility of wireless communication and avoiding the substantial overhead associated with per-transmission identifiers.

Background

The paper evaluates synchronization-based defenses against CrossLink. Perfect mixing, which coordinates identifier changes among co-located devices, can limit tracking but requires costly coordination across devices. Local synchronization, which rotates all identifiers on a single device simultaneously, remains sensitive to the synchronization period and does not fully prevent tracking.

The authors also note that per-transmission identifiers could approximate perfect mixing but would impose substantial overhead and reduce usability. They therefore identify the design of practical defenses that jointly preserve privacy and utility as an unresolved research problem.