How fairness works here
BearMark Arena keeps a tournament honest by making its draw and its results checkable by anyone — not by asking you to trust us. This page states exactly what the seal proves, and, just as plainly, what it does not.
What the seal says
- Verified — provably unbiasable
- The seeding draw was bound to a public drand beacon round that had not yet happened when the draw was committed. The beacon’s randomness — which nobody controls — decided the order, and anyone can replay it. Not even the organizer could have steered it.
- Verified — reproducible
- The event log replays to the exact final state shown, and every hash checks out. The result is reproducible from the record. (Shown when a draw is sealed but not yet confirmed against a public beacon.)
- Recorded — manual seeding
- The bracket was seeded by hand (the provably-fair draw was off, or a stuck draw was recovered manually). The standings still recompute from the recorded results by the stated rules, so you can check them — but the draw itself is not beacon-bound, so it carries no unbiasable claim.
- Draw in progress
- A verifiable seeding draw has been committed and is waiting for its public beacon round to land. The bracket appears once the round is published; until then there is nothing to bias and nothing to hide.
- Verification failed
- A check did not hold — the record does not replay to its claimed state, or a transcript or beacon signature did not validate. Treat the result with suspicion and look at the details.
How a verifiable draw works
- Before the draw, the tournament commits to its inputs — the participants and the exact procedure — and to a future public drand beacon round.
- That round has not happened yet, so its randomness is unknown to everyone, including us and the organizer.
- When the round is published, its randomness deterministically decides the seeding order. No human picks it.
- Anyone can re-derive the order from the same public beacon and the committed inputs, and confirm it matches what was published.
What proofmark checks (offline, trusting nobody)
proofmark is the free, open verifier. It runs in your browser or on your machine over the published dossier and re-checks, independently:
- that the event log replays to the claimed final state (nothing was quietly edited);
- that the definition hash and every state hash match;
- that each draw transcript is internally consistent and maps to the published order;
- that each bound drand beacon round’s signature is valid — so the randomness is the real public beacon, not a substitute.
Honest boundaries
The unbiasable seal is a specific, narrow claim. It does NOT mean “cheating is impossible.” Three boundaries are worth naming:
- Manual seeding is not unbiasable.
- If the provably-fair draw is turned off, or a stuck draw is recovered by seeding manually, the order is set by a person. The seal downgrades to “manual” and makes no unbiasable claim.
- Very large fields fall back to manual.
- The verifiable draw supports up to 108 participants. Above that, seeding falls back to manual rather than wedge the tournament — and the seal downgrades honestly, the same way.
- The commit-vs-publish ordering is not yet notarized (disclosure residual).
- The public beacon means the randomness cannot be predicted or controlled. But the moment of commitment relative to the beacon is, for now, the server’s own record. A determined organizer could in principle run the ceremony privately more than once and publish only a favorable outcome. A separate draw-time notary — an independent party that countersigns the single commitment before the round — closes this. Until it ships, we name the gap rather than paper over it.
Check it yourself
Don’t take our word for any of this. Open a tournament’s Verify page to re-run the checks in your own browser, or run the verifier from the command line over its dossier.json.
Try the demo’s Verify page →
Or run the CLI over any tournament’s dossier.json:
node packages/proofmark/dist/cli.js dossier.json