Marcin Pawlowski cad2bf51b2
blend: emission-model fidelity, and evidence tooling that covers every section
Second review pass, three findings.

Pending cancellations were a set, so a node that proposed twice before its next
cover emission forfeited only one and then over-emitted relative to its quota --
the precise uniformity cover traffic exists to preserve. Now a multiset.

The timeline drew the block proposer uniformly while quota.py used a stake-
weighted lottery, so the two halves of the cover-traffic model disagreed. The
timeline now takes the stake array. Concentration is visible in the bookkeeping: a
dominant proposer wins most proposals but rarely draws a cover slot to forfeit, so
cancellations redeemed fall from 107 to 28 -- the unredeemed backlog being exactly
the over-emission the stake ceiling describes.

data/report_numbers.py claimed to print every quoted value but covered only
sections 3.1-3.5 and 3.8. Extended to 3.9 correlated churn, 3.10 blending, mixing
and the quota ceiling, 3.11 the release designs, and the 3.4 attribution bracket;
the claim in data/README is corrected to say what it actually does.

Neither model fix moves a published number: the proposer identity does not enter
blending, mixing or timing, and repeat proposals are rare at the reported rates.
Two regression tests pin both.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
2026-08-06 18:00:02 +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 straight from the parquets here -- the §3.1§3.5 and §3.8 tables with their across-topology standard errors, and the §3.9§3.11 tables and the §3.4 attribution bracket from their own runs. 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.