PrivyWave: Privacy-Aware Wireless Sensing of Heartbeat
Yixuan Gao, Tanvir Ahmed, Zekun Chang, Thijs Roumen, Rajalakshmi Nandakumar
Deploy this for health monitoring in shared spaces where you need selective access—authorized caregivers get accurate readings while blocking surveillance. Works across 30-150 cm distances and 120° field of view.
Wireless sensors can now detect heartbeats through walls using RF and acoustic signals. Existing privacy solutions either block all sensing (killing utility) or operate post-capture (too late for selective access control).
Method: A key-based physical obfuscation system that generates cryptographically-determined decoy heartbeat signals. Unauthorized mmWave radar sensors show 21.3 BPM mean absolute error while authorized sensors maintain 5.8 BPM. For acoustic sensing, unauthorized error jumps to 42.0 BPM while authorized sensors achieve 9.7 BPM. The system works across modalities without per-modality customization by mixing real and decoy signals that only authorized devices can filter.
Caveats: Tested with 13 participants in indoor environments. Real-world deployment at scale unverified.
Reflections: Can adversaries with multiple synchronized sensors triangulate to defeat the decoy system? · What's the energy cost of continuous decoy generation for battery-powered wearables? · How does the system perform with multiple people in the same space?