Provably fair is a cryptographic method that lets you check, after a round has finished, that a crypto casino did not alter the result once it saw your bet.
It works by commitment. Before you play, the casino publishes a hashed “fingerprint” of a secret server seed. Your bets combine that server seed with a client seed you can change and a nonce that counts each bet. Afterwards, the casino reveals the original server seed, and you confirm it matches the fingerprint shown earlier and reproduces the exact results you saw.
What this proves is the integrity of each outcome: the operator could not swap the seed after the fact, and you helped determine the result. What it does not do is remove the house edge, improve your odds, or guarantee that a casino is licensed or will pay you. Provable fairness is about the honesty of the draw, not the generosity of the game.
For example, a dice site might show you a hashed server seed, let you set your own client seed, then after your session reveal the seed so you can re-run the maths yourself, or use an independent verifier, and confirm nothing was manipulated.
Related terms
- House edge
- On-chain deposit
- Our full guide: provably fair explained
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