Catalogues 5 biometric primitives in CSI that survive cross-environment
transfer by physical construction (not just statistical learning), with
quantified discriminability:
| Primitive | Bits | Invariance |
|------------------------------------|-----:|------------|
| Gait stride frequency | 5 | HIGH |
| Breathing rate + envelope | 5 | HIGH |
| HRV (rate-level only) | 4 | HIGH at rate, LOW at contour |
| Body-size RCS frequency response | 4 | MEDIUM (needs calibration target) |
| Walking dynamics (limb timing) | 7 | HIGH (if pose works cross-room) |
Composite biometric strength: ~12-15 bits realistic vs 25-bit independence
upper bound. Enough for household + building-scale ID; insufficient for
forensic / city-scale.
R15 strengthens the R14/R3/ADR-105 privacy framework: RF biometric is
PHYSICAL not learned, so the same primitive that enables empathic
appliances is a surveillance primitive that's harder to opt out of than
visual ID. There is no behavioural countermeasure short of jamming
(illegal) or physical alteration (impossible).
Surfaces required amendment to ADR-105 federation protocol:
'The federation aggregator MUST NOT receive any raw per-subject biometric
primitive. It MAY receive aggregated, MERIDIAN-normalised model deltas.
Per-subject primitives stay on-device.'
This becomes the requirements basis for ADR-106 (deferred DP-SGD ADR).
R15 closes the last unaddressed PROGRESS.md research thread. After R15:
- Closed: 'what RF biometrics exist and how do they invariantise' = answered
- Open: ADR-106, R6.1 multi-scatterer, R3 physics-informed env prediction,
R6.2 Fresnel-aware antenna placement
The per-occupant feature surface (R14 V1/V2/V3) is now fully grounded in
physics + constraints; remaining work is implementation, not research.
Composes with every prior thread:
- R5 saliency: primitive-specific maps
- R6 Fresnel: physical basis for RCS invariance
- R7 mincut: defends primitive-level poisoning
- R10 per-species gait: transfers to per-individual gait biometric
- R13 NEGATIVE: 5-dB-short wall rules out contour-level HRV
- R3: embedding space combines 5 primitives
- R14: all 3 verticals (V1/V2/V3) work with rate-level subset
Honest scope:
- Bit counts are upper bounds; 30-50% loss to noise/multipath
- Contour-level HRV not achievable (R13 wall)
- Walking dynamics 7-bit assumes pose-from-CSI works cross-room (unmeasured)
- Body-size RCS needs calibration target in new room
Coordination: ticks/tick-14.md, no PROGRESS.md edit.
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