05 — Experiment Protocol: Attacker vs. Protector

This is the "start today" deliverable from the brief: make one RuView node the attacker and one the protector, and measure whether protection drives identity recognition toward chance while keeping throughput above 95%. It is realized as a deterministic, reproducible experiment in v2/crates/wifi-densepose-privshield.

Because it runs on SYNTHETIC data (no radio is touched), its numbers describe the model, not real hardware — reproduced by cargo test, and to be re-established on silicon with a captured log before any deployment claim.

1. Setup

Protector node. Emits beamforming feedback shaped by the VEIL controls (keyed per-session fine-subspace rotation + configured feedback resolution and sounding overhead). Models a legitimate AP/STA protecting a room.
Attacker node. A passive sniffer that enrolls a template per candidate from captured reports, then classifies fresh captures (nearest-centroid) — the BFId-class re-identification threat.
Scene. SceneConfig default: 64-dim report, 8 comm dims, 16 candidate identities (chance = 1/16 = 6.25%), per-identity stable fine-block signature
- per-session environmental nuisance.

Two runs of the attacker are compared: shield off (the attacker sees raw reports) and shield on (every captured report is VEIL-protected). The same attacker faces both.

2. Metrics and acceptance bar

Metric	Definition	Bar
Re-ID accuracy, shield off	Top-1 identity accuracy on unprotected traffic	Must be well above chance (threat is real) — bar ≥ 0.5
Re-ID accuracy, shield on	Top-1 identity accuracy on protected traffic	Must fall into the chance band `1/N · 2 + 0.03`
Throughput ratio	Protected link capacity ÷ baseline capacity	≥ 0.95
Compliance	Emission energy ratio ≈ 1 and non-interfering	`is_compliant == true`

Overall passed() requires all four.

3. Results (SYNTHETIC, hyper-optimized default configuration)

Reproduce with cargo test -p wifi-densepose-privshield (all 35 tests + doctest pass). The default shield config is the optimize module's output — 96 Givens passes at 5-bit feedback resolution (see 08-optimization.md). Salient values from the reference run:

Metric	Value
Candidate identities	16
Chance level	6.25%
Chance band (acceptance)	≤ 15.5%
Re-ID accuracy, shield OFF	100.0%
Re-ID accuracy, shield ON	4.7%
Throughput ratio	97.60%
Emission energy ratio	1.000000
Overall verdict	PASS

Reading the result: the attacker is a perfect re-identifier without protection (the synthetic signatures are cleanly separable), and VEIL drives it to the chance floor (4.7% sits just below the ideal 6.25%, i.e. no better than guessing) — while the modeled link keeps 97.6% of its throughput and the emission conserves energy exactly (compliant, not jamming). The same collapse holds under a Cosine-metric attacker and at N=32, confirming it is a property of the signal, not the classifier.

4. Determinism and the witness

The experiment is byte-reproducible: no OS entropy, no wall-clock, no threads. proof::Proof folds the salient outputs (quantized to avoid last-bit f32 round-off) into an FNV-1a witness pinned as EXPECTED_WITNESS. Any drift in the PRNG stream, rotation schedule, throughput formula, or scene geometry changes the witness and fails witness_matches_pinned. This is the same deterministic-proof discipline as nvsim and the Python verify.py.

5. Sensitivity and what to vary next

ExperimentConfig exposes the levers for a fuller study:

scene.identities — larger N lowers the chance floor; confirm collapse holds as candidates grow.
scene.env_sigma / beam_amplitude — nuisance and comm energy; stress the separability assumption.
shield.feedback_bits — trace the privacy–throughput curve (the throughput tests already show coarse resolution costs more).
shield.givens_passes — mixing strength; fewer passes should degrade the collapse gracefully.
Stronger attacker — swap in a learned classifier to confirm the collapse is signal-level, not classifier-level (the argument says it must be, but a hardware study should verify).

6. Path to a real two-node measurement

The synthetic experiment is the design proof. The hardware path (per CLAUDE.md, requires a captured log to claim MEASURED):

Two ESP32-S3/C6 or Nexmon-capable nodes: one runs Wi-BFI capture (attacker), one runs a VEIL-shaped feedback profile (protector).
Enroll and test the same BFId-style classifier on captured BFI, shield off vs. on; log throughput via iperf across the legitimate link.
Success = the same shape as §3 on real captures, with the boot/runtime log as the witness. Until then, all defense numbers remain SYNTHETIC.

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