What is provably fair?
Provably fair uses cryptographic data to let you verify a casino round.Before play, a supported game commits to a secret server seed. After play, it publishes the inputs and algorithm needed to recompute the displayed crash multiplier or dice roll. The scope and exact calculation vary by game, so verification must follow that game's documented implementation.
The three ingredients
- Server seed — a secret random string the casino generates. Before you play, it publishes only the SHA-256 hash of it: the commitment.
- Client seed — a string that participates in the calculation and that a player may be able to choose. Choosing it after the server-seed commitment helps avoid one party selecting every input.
- Nonce — a counter that increases by one per bet, so every round under the same seed pair gets a unique result.
How a round is settled
The outcome is derived deterministically, often with HMAC-SHA256 over documented seed and nonce inputs. Input order and result conversion are implementation-specific. The resulting hash is converted to a game value — a dice roll, a crash point or a card. When the seed pair is rotated, the casino reveals the old server seed. First, confirm that the revealed server seed's SHA-256 equals the pre-round commitment. The hash match shows that the seed was fixed before you played. Then, recompute the documented algorithm and confirm that it reproduces the result you recorded. The RTP Ledger verifier tool performs both checks in your browser for its explicitly supported Stake Dice inputs.
Have the revealed server seed, client seed, nonce and recorded Stake Dice result? Recompute it locally with the narrowly scoped verifier.
Open the Stake Dice verifier →Why a verifier is not a predictor
A legitimate provably-fair verifier checks a completed round after the server seed is revealed. With a properly generated secret seed, its earlier SHA-256 commitment does not expose the seed or the next result in a practically reversible form. A site claiming it can predict future crash points, dice rolls or slot outcomes from that commitment is not performing the verification described here. If a secret seed were weak, reused incorrectly or leaked, that would be an implementation failure — not a feature of provably fair verification.
What a successful check proves
A passing verification is evidence that the supplied inputs reproduce the recorded round and that the revealed server seed matches the earlier commitment. It does notprove the entire casino system or that the game is good value. The game math can still contain a house edge. An instant-bust probability alone does not determine that edge; the named implementation's complete outcome distribution and payout formula do. Verification does not change the house edge. Think of it as an integrity check, not an advantage.
It also only covers the games wired into the system — usually the casino's own originals. Third-party slots generally do not expose the seed inputs used by casino originals. Look for the actual rules, licence and independent testing evidence where available. A recorded RTP describes theoretical return, not proof that a game or operator is fair.
Practical hygiene
- Set your own client seed when you start playing, and rotate it occasionally.
- Verify recorded rounds after a seed rotation; spot checks can reveal a mismatch but cannot audit untested rounds.
- If a revealed seed fails the commitment check, save screenshots and escalate the issue. The check is designed to detect a seed mismatch.
- Remember that a verified fair game is still a negative-EV game.
FAQ
Does provably fair mean the game is fair to play?
A successful check shows that the revealed server seed matches its earlier commitment. The check also shows that the published calculation reproduces the recorded round from the supplied inputs. It does not prove favourable odds, every part of the implementation, or any withdrawal claim.
Can a casino cheat a provably fair system?
A changed revealed seed or a result that does not match the published calculation should fail verification. That check still does not audit the user interface, seed generation, omitted inputs, untested rounds or games outside the scheme.
Are slots provably fair too?
Usually not through the casino seed workflow. Third-party slots generally do not expose the server seed, client seed and nonce needed for this check. Evaluate their actual game rules, licence and testing evidence where available; an RTP figure alone does not prove fairness.
18+ · Gambling can cause losses and never guarantees a profit. BeGambleAware.org
