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Provably Fair Dice Verifier

Recompute any bitcoin dice roll from its seeds and nonce, entirely in your browser. If the number the casino showed you does not match the number this tool derives, you have cryptographic proof something is wrong.

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Fill in the fields and hit Verify.

How to verify a dice roll

  1. Before playing, copy the server seed hash the casino shows you. That hash is the site's commitment: it cannot change the seed afterwards without the hash failing.
  2. Play your session. Every bet increments the nonce by 1 under the same seed pair.
  3. Rotate your seed in the casino's fairness settings. The old server seed is revealed.
  4. Paste everything here. The tool checks that SHA-256 of the revealed seed equals the committed hash, then recomputes any roll with HMAC-SHA256(serverSeed, clientSeed:nonce).

The construction differs slightly between operators. Most dice-first sites use the generic mod-10000 method; Stake's Originals dice uses a byte-fraction float scaled to 0.00-100.00. Pick the right preset above, and see our guides to how provably fair works and seed rotation for the theory.

Everything runs client-side with the browser's Web Crypto API; your seeds never leave this page. Practice the full flow risk free on our dice simulator, which commits and reveals seeds the same way.

Verifier FAQ

What does a mismatch mean? +
If the seed hash check fails, the site revealed a different seed than it committed to. If the hash matches but the roll differs, the site is not deriving rolls from the published construction. Either way, withdraw and document everything.
Why do I need to rotate my seed before verifying? +
The server seed stays secret while it is in use; otherwise you could predict future rolls. Rotation retires the seed pair, at which point the site reveals it and every past roll becomes checkable.
Which method do I pick for my casino? +
Stake Originals dice uses the Stake-style float method. Most dedicated dice sites (and our simulator) use the generic HMAC mod 10000 method. The casino's fairness page documents its exact construction; if it matches neither preset, the code differs in details like nonce separators.
Does verifying prove the site is fair overall? +
It proves each verified roll was determined by the committed seeds and not manipulated after the fact. It does not change the house edge, which is separate math you can check with our house edge calculator.