Marcin Pawlowski fb49a790fc
blend: make sections 3.11 and the attribution bracket reproducible
Review finding: the timing study and the neighbourhood-confidence numbers were
produced by ad-hoc analysis, not by the simulator. timing_linkability,
neighbourhood_confidence and mean_upstream_hops had no callers outside their own
modules; min_blend_delay and release_mode were declared on SweepConfig, validated
and keyed, but never read by sweep.py, so a YAML setting them was silently
ignored; and propagation.py called mix_wait without the minimum, leaving the knob
inert on the delay tables of 3.1-3.2. Section 6 promised every number was
reproducible and data/README claimed to hold the evidence behind every number --
both were false for 3.11.

Now wired end to end: release_designs() is a real sweep axis, the engine measures
the timing attack per design and records it in traffic.parquet, and the deanon
table carries the full attribution bracket (local confidence, attributable
fractions, upstream hops, neighbourhood confidence). Added configs/timing.yaml
and a make target.

The committed sweep reproduces 3.11: MAP success 0.993/0.905/0.683 for clock and
0.989/0.832/0.550 for jitter across the swept rates, and the minimum interval
changes nothing (0.993 vs 0.993). Evidence checked in under data/timing.

Three regression tests pin the wiring so a measure cannot go back to living only
in analysis.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
2026-08-06 18:00:01 +02:00
..

Evidence of record

The sweep outputs behind every number in the report. The simulator does not commit its own runs/ directory — these are the copies of record, kept so that any figure or table can be re-derived, or challenged, without re-running hours of compute.

Each run directory holds the three tables the simulator writes: propagation.parquet, adversary.parquet and deanon.parquet.

directory config sampling backs
default/ configs/default.yaml 1 000 rounds × 8 seeds = 8 000/cell §3.1§3.5 — delay, observation, eclipse, deanonymization, delivery, coverage
redundancy/ configs/redundancy.yaml 1 200 × 8 = 9 600/cell §3.8 — messaging redundancy R = 1…4
percolation/ configs/percolation.yaml 800 × 8 = 6 400/cell §3.5 — the churn threshold u_c = 1 1/(degree 1)
correlated-churn/ configs/correlated-churn.yaml 800 × 8 = 6 400/cell §3.9 — correlated AS/region outages vs uniform churn
fullscale/ configs/fullscale.yaml 64 × 3 = 192/cell §5 — the 10⁶ scaling check (deliberately lighter; not a source of headline numbers)
cover-traffic/ configs/cover-traffic.yaml 900 s timeline × 4 seeds §3.10 — blending, mixing, and the emission-quota stake ceiling. Carries a fourth table, traffic.parquet
timing/ configs/timing.yaml 120 s timeline × 3 seeds §3.11 — the two release designs under a timing attack, and the minimum-interval control

The linkability results (§3.6§3.7) and both deanonymization rates are closed forms over these tables rather than separate measurements, so they have no run of their own — blend.linkability derives them and make verify checks them against Monte-Carlo.

Regenerating the report's numbers

python report_numbers.py

prints every quoted value with its across-topology standard error, straight from the parquets here. That is the fastest way to check a table in the report against its evidence. It takes optional paths (report_numbers.py <default> <redundancy> <percolation>) if you want to point it at fresh runs instead.

Regenerating the data itself

From tools/simulators/blend: make sweep, make redundancy, make percolation, make correlated-churn, make sweep-fullscale. Results land in that simulator's runs/<timestamp>_<label>/. Note that the seed streams depend on the configuration, so re-running reproduces the statistics, not bit-identical numbers, unless the config is unchanged — in which case it does reproduce exactly.

Two runs from the same session are deliberately not kept: the smoke runs (throwaway, far too noisy to interpret) and an earlier 144-rounds/cell redundancy grid that was superseded because its sampling error produced a non-monotonic delivery curve — the reason redundancy/ samples 9 600.