Provably Fair Verifier
Use this provably fair verifier to independently check crypto casino game results. Paste your server seed, client seed, and nonce to confirm any round was dealt honestly.
How Provably Fair Works
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Before each round, the casino commits to a server seed by publishing its SHA-256 hash. You provide a client seed. Neither party can change their seed after the commitment.
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After the round, the casino reveals the server seed. You can verify the hash matches the commitment, then recalculate the game result yourself using the server seed, client seed, and nonce.
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If the result matches what you experienced in the game, the outcome was fair. If it does not match, the casino altered the result.
How This Verifier Works
This tool replicates the cryptographic process that provably fair casinos use to generate game outcomes. It takes your server seed, client seed, and nonce, runs them through HMAC-SHA256, and converts the resulting hash into a game result (crash multiplier, dice number, etc.). If the output matches what the casino displayed, the round was determined honestly before you bet.
The key insight: the casino commits to a server seed by publishing its SHA-256 hash before the game. Since SHA-256 is a one-way function, the casino cannot change the seed after committing. When the seed is revealed later, you can hash it yourself to verify it matches the commitment. This is what makes the system trustless: you do not need to trust the casino, you can verify every result independently.
For a full explanation of the cryptography behind this system, read our provably fair guide.
Frequently Asked Questions
What does provably fair mean?
Provably fair is a cryptographic system that lets you verify every game result was determined before your bet was placed. The casino commits to a server seed (hidden behind a hash), you provide or accept a client seed, and both are combined with a nonce to generate the game result. After the round, you can check the server seed against its hash to confirm nothing was changed.
How do I verify a provably fair result?
After revealing the server seed (usually when you rotate to a new one), paste the server seed, client seed, and nonce into this verifier. The tool hashes them using the same algorithm the casino uses (typically HMAC-SHA256) and converts the output to a game result (crash point, dice roll, etc.). If the result matches what the casino showed you, the round was fair.
Which crypto casinos support provably fair games?
Most crypto-native casinos offer provably fair originals including crash, dice, mines, plinko, and limbo. Traditional slot or live dealer games from third-party providers are not provably fair. Stake, BC.Game, Roobet, and BetFury all offer provably fair crash games. See our full list on the provably fair casinos page.