Provably Fair Verifier
Quick Answer
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 to Use This Verifier
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In your casino account, navigate to the provably fair section and rotate to a new server seed. The casino reveals the previous server seed.
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Copy the revealed server seed. Note your client seed (you may have set a custom one; if not, find the default in the casino fairness section).
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Find the nonce for the round you want to verify. Each bet increments the nonce by one.
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Paste all three values here and click Verify. The hash and computed game result appear instantly.
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Compare the result to what the casino displayed. A match confirms the round was not manipulated.
Frequently Asked Questions
How do I verify a provably fair crash result?
Rotate to a new server seed in your casino account settings. The casino reveals your previous server seed. Paste it into this verifier along with your client seed and the nonce (round number) you want to verify. The tool computes HMAC-SHA256(serverSeed, clientSeed-nonce) and converts the hash to a crash multiplier using the standard formula. If the result matches what the casino showed, the round was fair.
Does this verifier send my seeds anywhere?
No. All computation uses the Web Crypto API in your browser. Your seeds never leave your device. The HMAC-SHA256 hash is computed entirely client-side. You can disconnect from the internet and the verifier will still work on previously loaded seeds.
What is an HMAC-SHA256 hash?
HMAC-SHA256 is a cryptographic message authentication code using SHA-256. It takes a key (server seed) and a message (client seed combined with the nonce) and produces a deterministic 256-bit output. The same inputs always produce the same output, and it is computationally impossible to reverse or predict. This property makes it suitable for provably fair game verification.
Which casinos use this provably fair system?
Stake, BC.Game, Cloudbet, Shuffle, Duelbits, Crashino, and most crypto casino originals use a standard SHA-256 HMAC chain. The exact conversion formula (how the hash becomes a crash point or dice result) varies slightly between platforms but follows the same cryptographic foundation. Always check the casino documentation to confirm the formula used.