How provably fair works, in plain terms
Before every bet, the operator commits to a random “server seed” by publishing a SHA-256 hash of it. You then supply a “client seed” (your browser generates one, or you can pick your own). The bet outcome is computed from both seeds. After your session, the operator reveals the original server seed. You hash it and check that it matches the original published commitment — proving the operator couldn’t have changed the outcome after seeing your bet.
For the full technical explanation, see the Bitcoin Wiki entry on provably fair gambling.
What provably fair does — and doesn’t — protect against
- Protects against: the operator changing the outcome of an individual bet after seeing your seed. This is the historic “trust the casino’s RNG” problem, solved.
- Doesn’t protect against: a rigged house edge (the math is still in the operator’s favour by design), withdrawal delays, bonus T&C abuse, or insolvency. Provably fair is one trust layer, not all of them.
Which games are provably fair?
Provably fair applies almost exclusively to original in-house games: dice, crash, plinko, mines, keno, hilo, blackjack and a handful of slot titles built by the operator. Third-party slots from providers like Pragmatic Play, Evolution and Hacksaw Gaming are not provably fair — they rely on the provider’s RNG certification (typically by GLI or iTech Labs).
How to verify a bet yourself
Every reputable provably-fair casino exposes a “verify” page that lets you:
- See the original server-seed hash you were given before the bet.
- See the revealed server seed after rotation.
- Re-hash the revealed seed and compare against the original hash.
- Re-run the deterministic outcome calculation with both seeds and your bet number.
If you get the same outcome the casino paid out on, the bet was provably fair. Independent verifier tools exist for popular game engines — open-source implementations on GitHub let you double-check the casino’s math without trusting its UI.
Which BettingPair-tracked operators offer provably fair games?
Crypto-first operators in our decision hub with a meaningful provably-fair catalogue include Stake.com, BitStarz, and Crypto Games. Open the individual reviews for the current verification flow per brand.