What is Provably Fair? How to check results yourself
Provably Fair is a method that is meant to prove that an online game's result was not changed afterwards. The operator fixes the result in advance, and you can recalculate it after the round.
The three building blocks
- Server seed: a secret key of the operator. Before the round only its hash (a fingerprint) is shown.
- Client seed: a value you can set yourself or that is generated at random.
- Nonce: a counter that goes up by one with every round.
The result is calculated from server seed, client seed and nonce. Because the server seed is only revealed after the game, the operator can no longer change the result.
How to check a round
- Note the hash of the server seed before you play.
- Play the round.
- Have the server seed shown to you after the game.
- Check that the hash of the revealed seed matches the hash shown beforehand.
- Calculate the result with the revealed seed, your client seed and the nonce using the operator's formula.
The formula is usually in the operator's fairness information. Many operators also offer a checking script.
What Provably Fair does not mean
- It does not mean that you will win. The winning chance is in the game rules and is often still in the house's favour.
- It only checks that the result matches the round. It does not check whether the payout is correct.
- A missing or wrong hash is a warning sign.