ruvnet--RuView/docs/research/privacy-shield/02-threat-model.md

02 — Threat Model

VEIL protects a physical space (a room, a ward, a boardroom, a SCIF) from unauthorized WiFi-based inference of who is present and what they are doing, without denying the space its own working WiFi. This file states the adversary classes, exactly what VEIL defends, and — just as importantly — what it does not.

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1. Assets

Asset	Why it matters
Identity linkage	Re-identifying a specific person across time/sessions from their RF signature (BFId-class attack)
Occupancy / presence	Whether the space is occupied, and by how many (LeakyBeam-class, through-wall)
Activity / motion	Gait, gestures, keystrokes, respiration inferred from channel dynamics (BeamSense-class)
Communication utility	The legitimate WiFi link must keep working (≥95% throughput bar)

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2. Adversary classes

Class	Position	Capability	In VEIL scope?
A1 — external passive sniffer	Outside the trust boundary (adjacent room, van, hallway), monitor mode	Captures plaintext BFI/CSI for every station; runs BFId/LeakyBeam/BeamSense offline	Primary target — yes
A2 — external active sensor	Nearby, transmits its own probing/sounding to solicit measurable responses	Elicits sensing responses; 802.11bf "active" mode	Partial — cadence randomization + non-response policy help; full defense needs MAC-layer policy
A3 — associated but curious AP	Inside the link; the party VEIL shares keys with	Sees the un-rotated report by construction	Out of scope — this is BFLD's detection/privacy-class problem (ADR-118/141)
A4 — supply-chain / firmware	Compromised radio firmware	Can bypass any transmit-side control	Out of scope (integrity problem, not a waveform problem)
A5 — physical / RF-denial	Wants to block WiFi	—	Explicitly rejected: VEIL never jams

VEIL's design centers on A1, the attacker the literature demonstrates and the one no shipping product addresses.

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3. What VEIL guarantees (and the evidence class)

1. Cross-session identity unlinkability against A1. Because the fine-subspace signature is rotated by a fresh secret orthogonal transform each session, an A1 attacker cannot average captures back to a stable per-person template. Evidence: SYNTHETIC — re-ID collapses from 100% to ~chance in the reference experiment (cargo test); real-silicon witness is future work.
2. Communication preservation. The transform is key-reversible by the legitimate receiver, and acts only on the identity-bearing fine subspace, so link throughput stays ≥95%. Evidence: SYNTHETIC model + MEASURED external corroboration (DySPAN 2026: fine-resolution feedback shaping is near-free).
3. Compliance. The transform is orthogonal ⇒ energy-preserving ⇒ adds no interfering emission ⇒ not jamming. Evidence: machine-checked energy ratio = 1.000000 in the compliance module; statutory analysis in 04-compliance-and-regulatory.md.

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4. What VEIL does NOT do (non-goals, stated to prevent over-claiming)

• It does not hide identity from the associated AP (A3). That party holds the session key. Protecting against a malicious AP requires detection and policy (BFLD), not waveform shaping.
• It is not RF denial or jamming. It never degrades another station's link.
• It does not, by itself, defeat within-session motion detection. A single session's rotation is fixed, so coarse presence/motion may still be inferable within one capture window; sounding-cadence randomization mitigates but does not eliminate this. Identity re-ID (the brief's metric) is the guaranteed target; motion obfuscation is partial and tracked as future work.
• It is not a camera-grade or medical-grade claim in any direction.
• It is not validated on hardware yet. All quantitative defense results are SYNTHETIC until a captured boot/runtime log exists (CLAUDE.md hardware rule).

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5. Trust boundary

        ┌────────────────────── protected space ──────────────────────┐
        │                                                              │
        │   [person]      [person]        legitimate STA ⇄ AP (VEIL)   │
        │      │             │                 │  shares session key   │
        │      └──── RF ──────┘                 │  rotates fine subspace│
        │            reflections                ▼  of its own BFI       │
        │                               compliant, key-reversible,      │
        │                               energy-preserving emission      │
        └───────────────────────────────────────┬──────────────────────┘
                                                 │  plaintext BFI on air
                                                 ▼
                    A1 external passive sniffer (monitor mode)
                    sees a freshly-rotated signature each session
                    → cannot build a stable per-person template
                    → re-identification → chance

The key never crosses the boundary to A1. The AP inside the boundary is trusted for key-sharing (A3 out of scope). No emission crosses the boundary with intent or effect of interfering with another station (A5 rejected).