Provably fair is a commit-and-reveal system. The casino locks in its secret seed before you bet by showing you its hash, you add your own seed, and each result is calculated from both. Later the casino reveals its seed and anyone can recompute every result. It proves results weren't changed. It doesn't remove the house edge.
The three ingredients
| What it is | Who controls it | |
|---|---|---|
| Server seed | A long random secret | Casino. Hidden until you rotate, but its hash is shown up front |
| Client seed | A string you can set to anything | You |
| Nonce | A counter: 0, 1, 2… one per bet | Increases automatically |
The commit: hashing
A hash function like SHA-256 turns any input into a fixed-length fingerprint. Change one character of the input and the fingerprint changes completely; and you can't go from the fingerprint back to the input. By showing you the hash of the server seed before you bet, the casino commits to that exact seed without revealing it.
The result: combining the seeds
For each bet the game combines server seed, client seed and nonce into a new hash and turns the hash into a result. For Plinko, the hash becomes a series of numbers between 0 and 1, one per row; below 0.5 means left, otherwise right. Count the rights and you have the slot.
The reveal: verifying
When you rotate your seed pair, the casino reveals the old server seed. Now you can:
- Hash the revealed seed and check it matches the hash you were shown.
- Recompute every bet from the seeds and nonces.
- Compare with what the casino paid.
How to check a bet, step by step
- Before you play, find the fairness or provably fair settings. The casino shows the SHA-256 hash of its active server seed. Save it.
- Set your own client seed in the same place. Anything works; what matters is that you chose it.
- Play. Each bet on this seed pair uses the next nonce, usually starting at 0.
- Rotate the seed pair when you want to check. The casino reveals the old server seed and starts a new pair.
- Check the commitment. SHA-256 of the revealed seed must equal the hash you saved in step 1. If it doesn't, the seed was changed after you bet.
- Replay the bets. Enter the revealed server seed, your client seed and the nonce of a bet into a verifier: ours or the casino's own. You should get the same result.
- Compare the payout. Check that the multiplier you were paid matches the casino's table for that result.
A few bets per rotation is enough. Any manipulation would show up in a random sample.
What provably fair proves - and what it doesn't
Proves: the casino committed to its seed before you bet; your seed was part of every result; results can be recomputed by anyone.
Doesn't prove: that the payout table is fair to you (the house edge is in it, openly); that withdrawals will be processed; that the casino's described algorithm is the one it runs - unless someone reproduces it against real rounds. That last check is exactly what our verified label means.
See how the payout tables turn into RTP on the 16-row odds page.
Sources
- BCH.games: Randomization and reference code