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Privacy Shield Research Bundle — WiFi Veil
WiFi Veil (codename VEIL — Verifiable Emission-shaping for Identity-Leakage prevention) is a privacy firewall for WiFi sensing: it prevents unauthorized identity and activity inference from a room's WiFi while preserving normal communications. It is the countermeasure counterpart to BFLD — where BFLD detects when beamforming feedback becomes identifying, WiFi Veil acts by shaping the node's own compliant waveform (channel sounding, precoder phase, beam/feedback schedules) so identity and activity inference fail, while a legitimate receiver sees an essentially unchanged link.
This must use compliant waveform controls, never jamming. Every technique here operates on the defender's own legitimately transmitted, standards- conformant frames. Nothing adds energy to interfere with another station's transmission (the statutory definition of jamming, 47 U.S.C. §333/§302a).
Table of contents
| File | Purpose |
|---|---|
| 01-sota-survey.md | State of the art: identity/activity inference attacks (BFI + CSI), the IEEE 802.11bf-2025 standard, and privacy-preserving countermeasures |
| 02-threat-model.md | Adversary classes, what WiFi Veil defends and what it explicitly does not, trust boundary |
| 03-countermeasure-design.md | The compliant waveform controls, the separable-subspace principle, keyed Givens-rotation shield, and how it maps to the crate |
| 04-compliance-and-regulatory.md | The legal line between compliant waveform control and jamming, with statutory citations |
| 05-experiment-protocol.md | The attacker-vs-protector experiment: metrics, acceptance bar, reproducer, and results |
| 06-market-and-buyers.md | First buyers, procurement drivers, competitive landscape, and the standards-body gap |
| 07-implementation-and-roadmap.md | Crate layout, reuse map, hardware path, phased rollout, and open problems |
| 08-optimization.md | Hyper-optimization: throughput-optimal feedback resolution, minimum robust mixing budget, Pareto frontier, and the adopted config |
| 09-sota-update-2026.md | 2025–2026 SOTA update (verified, cited): stronger attacks (BFI→CSI reconstruction, through-wall vitals, keystroke), validated compliant defenses, and the derived WiFi Veil improvement backlog |
Formal decision: ADR-288.
Reference implementation: v2/crates/wifi-densepose-privshield.
Executive summary
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The threat is real and now standardized. IEEE 802.11ac/ax beamforming feedback (BFI) — the compressed Givens-rotation angle matrices (φ/ψ) a client sends the AP — travels unencrypted on the management plane. Any device in monitor mode can capture it for every client at once, no network access, and the target need carry no device. BFId (KIT, ACM CCS 2025) re-identifies individuals from BFI alone; LeakyBeam (NDSS 2025) detects occupancy through walls at ~20 m from BFI; BeamSense recognizes activities at up to 99.28% from BFI. IEEE Std 802.11bf-2025 (published 26 Sep 2025) standardizes the sensing measurement/feedback surface these attacks abuse.
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The standards body declined to fix it. A 2023 proposal for a BFI "secure transmission mechanism" (IEEE 802.11-23/0782) was withdrawn — the working group did not align on characterizing sensing privacy as a distinct problem. 802.11bf shipped without privacy protections. This is the single strongest demand signal: the gap is structural and acknowledged.
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No targeted anti-sensing product ships (as of 2026). Every countermeasure in the literature — IRShield, PhyCloak, MIMOCrypt, DP-Givens dithering, ScatterShield — is research-stage. The only shipping substitute is broadband RF shielding (SCIF/TEMPEST film/paint), which is blunt: it kills all RF and cannot coexist with wanted WiFi. The whitespace is a selective, coexisting, software/PHY shield.
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The WiFi Veil mechanism. Identity leaks through the fine cross-subcarrier phase structure of a beamforming report; throughput rides the dominant beam direction. These are (mostly) separable subspaces. WiFi Veil composes extra keyed Givens rotations over the fine subspace only. The rotation is orthogonal (energy-preserving ⇒ not jamming), keyed per session (the legitimate receiver inverts it ⇒ throughput preserved), and fresh each session (a sniffer cannot average it back ⇒ re-ID collapses to chance).
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Measured on the reference model (SYNTHETIC), at the hyper-optimized operating point. On the default synthetic scene (16 candidate identities), a passive re-identifier scores 100% with the shield off and 4.7% with it on (chance = 6.25%), while modeled link throughput stays at 97.6% of baseline and the emission energy ratio is 1.000000 (compliant). The shield config is chosen by the
optimizemodule — 96 Givens passes (2× the proven- minimum 48 for robust collapse across both attacker metrics and N∈{16,32}) at 5-bit feedback resolution — not hand-picked (see 08-optimization.md). Reproduce:cargo test -p wifi-densepose-privshield. -
Scope, honestly. WiFi Veil defends against a third-party passive sniffer. It does not hide identity from the associated AP (that party holds the key) — that is BFLD's detection/policy problem. WiFi Veil is a reference model, not hardware: real-silicon validation (per CLAUDE.md) is future work with a captured-log witness.
Evidence discipline
Per repository policy, every quantitative claim is tagged:
- MEASURED — from a cited primary source with its metric and conditions.
- CLAIMED — asserted by a source (vendor PR, press, standards minutes) without an independent measurement.
- SYNTHETIC — produced by WiFi Veil's own deterministic model; reproduced by
cargo test, describing the model and not real hardware.
WiFi sensing is never presented here as camera-grade, and no WiFi Veil result implies a defense guarantee on real silicon until a hardware witness exists.