How to use the verifier

What you need

To verify a bet you need four values from the casino:

At most crypto casinos these live in a "Fairness", "Provably fair" or "Seeds" panel, usually reachable from the game screen, your account settings, or by clicking a bet in your history.

Step by step

1. Rotate your seed. You cannot verify bets made with the active server seed, because it is still secret. Rotate or change your seed pair; the casino then reveals the previous server seed.
2. Copy the values. Copy the revealed server seed, the client seed used for the bet, and the bet's nonce. Copy the hashed server seed you noted before playing, if you have it.
3. Check the commitment. Paste the server seed. The verifier shows its SHA-256 hash. It must match the hashed server seed shown before you played, exactly.
4. Choose the game and settings. Select dice, limbo, plinko or mines and enter any settings that affect the result: the number of plinko rows (8 to 16) or the number of mines. Limbo results assume a 1% house edge.
5. Read the result. The verifier recomputes the outcome from HMAC-SHA256(serverSeed, clientSeed:nonce:round), using four bytes per float and moving to the next round when a game needs more than eight floats. Compare it with the result in the casino's bet history. For plinko, the verifier shows the path and landing slot; look up the multiplier in the casino's payout table for your row count and risk level.

Reading the result

• Hash matches and result matches. The bet was generated from the committed seeds as documented. This is what you should see.
• Hash matches, result does not. Check the obvious first: correct nonce (some casinos start at 0, some at 1), correct client seed for that bet, correct game settings. If everything is right, the casino may use a different formula from the common one; check its documentation. If it uses the common scheme and still does not match, that is a serious finding. Please send us the details through the feedback form on our guides.
• Hash does not match. The revealed server seed is not the one the casino committed to. Make sure you are comparing the right seed pair. If you are, results from that seed cannot be trusted. Stop playing and report it.

Limits of provably fair

• It does not change the house edge. A verified game with a 1% edge still costs 1% of everything you wager on average.
• It covers only games built for it. Third-party slots, live dealer tables and most sportsbooks are not verifiable with seeds; see which casino games are provably fair. Their fairness rests on lab testing and licensing instead.
• Implementations differ. This verifier follows the most common scheme. Casinos may differ in the message format, byte conversion, game formulas or nonce start, so always read the casino's own fairness page.
• It says nothing about payouts. A casino can run perfectly fair games and still be slow to pay or refuse withdrawals.
• Shared-seed games work differently. Multiplayer games such as crash often use a published hash chain rather than your own seeds.

Privacy

The verifier runs in your browser. Nothing you enter is sent to us.

Sources

• https://pigmo-doc.gitbook.io/pigmo.com/fairness/implementation
• https://docs.rs/crate/fair/latest/source/src/rng.rs