Before the round, the operator publishes a cryptographic hash of the server seed it will use; after the round, it reveals the seed. Because the hash locks the seed in place, and the result is computed from that seed plus inputs you can see, you can recompute the outcome and confirm it was fixed before any bets were visible. Crash games popularised the scheme, and it is genuine: manipulation of a committed round would be detectable.
What the proof does not cover is the formula the seed feeds. The house edge lives inside that published formula, and the hash chain authenticates rounds drawn from a 1% game and a 5% game with equal rigour. Provably fair is a complement to licensing, not a substitute: it verifies the draw, while the licence is what covers everything else, from the game's stated rules to whether a withdrawal is honoured.
Why it matters
Provably fair is often marketed as if it made a casino trustworthy overall. It proves one precise thing, non-manipulation of committed rounds, and proving that thing says nothing about the price of the game or the conduct of the operator.
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