Fairness policy

Short version

• Before play, we publish a hash commitment to the hidden server seed.
• After the round ends, we reveal the server seed used for that round.
• You can paste the round values into the round checker.
• If the checker matches, the revealed seed and stored outcome match the earlier commitment.

Crash mixes in public randomness that does not exist yet

Each Crash round starts by publishing a commitment: the hash of a fresh hidden server seed, plus the number of a specific future round of the drand "quicknet" public randomness beacon (an independent network operated by the League of Entropy, including Cloudflare). That drand round is chosen so it is only published after betting closes. The crash point is computed from the server seed and that drand value together.

Because half of the input does not exist while bets are open, nobody — not the game server, not anyone with database access — can know or influence a crash point before betting closes. Every drand value carries a BLS signature that anyone can verify forever against the network's published group key; the server rejects any beacon value that does not verify, and the round checker performs the same verification.

If the drand network is unreachable when a round should start, the round is voided before any outcome exists: all bets are refunded and the server seed is revealed in a public void record, so once the beacon is available anyone can compute what the voided round would have paid. Selective voiding is therefore externally detectable. The scheme still cannot force the service to stay online; auditors should archive commitments and investigate unexplained void patterns.

Rounds played before the beacon cutover used a pre-published SHA-256 preimage chain (a finite sequence of seeds whose anchor hash was staged publicly at least 24 hours before use). Those historical rounds remain verifiable forever: the checker proves each revealed seed hashes back to its staged anchor at its exact committed position.

Coinflip freezes the match before final entropy

A current Coinflip round first commits the hidden server seed, nonce, creator side, exact item/value snapshot, and odds policy. The creator's browser then adds a random contribution that is stored once and cannot be replaced. After the opponent's exact funded custody—or the exact reserved bot basket—is fixed, a second commitment binds both sides, participant identities, items, values, funding type, and bot persona.

The second authenticated browser contribution is accepted only after that custody write. Storing it atomically starts the countdown, so there is no funding timeout or automatic reservation release after the final result becomes knowable. There is no server-generated fallback entropy. A disconnected participant can resume the same locally stored contribution, but this integrity rule also means an absent participant can delay settlement rather than being silently replaced.

The completed result includes the full transcript and both contributions. The checker recomputes the creator commitment, full-match commitment, combined client seed, weighted ticket, winning side, and winner against the server seed revealed after settlement.

How to check a round

1. Open the finished round from your history.
2. Copy the revealed server seed, seed hash, round ID, and the game-specific inputs shown. Crash loads its committed drand round and signature by round ID (historical rounds load their chain position and anchor); Coinflip loads its stored transcript by round ID.
3. Paste them into the round checker.
4. Compare the checker result with the result shown on the site.

What stays hidden during play

The live server seed is not shown while it can still affect a round. Showing it early would let people predict results. It is only revealed after it is no longer usable for future play.

Game edge

Game economics are defined by the settlement engine and verifier scripts. Where a game publishes a live numeric edge, we test that display against the engine before release. For games without a numeric in-game edge display, completed rounds remain independently checkable through the verifier.

If something does not match

A checker mismatch is treated as a serious incident. Email support@rustsnowball.com with the round ID and the values you used.