- Rotate your client seed. In the game's Fairness panel, click "New seed" — this forces the casino to reveal the old server seed.
- Copy the revealed server seed. It will be a long hex string. Copy it along with the originally-shown SHA-256 hash.
- Re-hash the seed. Run
echo -n <seed> | shasum -a 256(macOS/Linux) or use any online SHA-256 tool. The output must match the originally-published hash exactly. - Re-compute the round. Plug the server seed, client seed and nonce into the game's open-source verifier (or a quick Node script using
crypto.createHmac("sha256", serverSeed).update(clientSeed + ":" + nonce + ":0")) and confirm the output equals your published result. - Repeat across multiple bets. Verify a handful of nonces from the same session — if all match, the casino did not change a single outcome.
Where to verify, by casino
Stake, BC.Game, Shuffle, Rollbit and Duel.com all expose a Fairness tab on every original game with seeds, nonces and a one-click verifier. Read the full provably fair casinos guide for operator-by-operator notes.
Frequently asked questions
Do I need to be a developer to verify a hash?
No. Every major provably fair casino ships an in-site verifier that shows the seeds, nonce and expected result. You only need command-line tools if you want to double-check independently.
What if the hash does not match?
If the SHA-256 of the revealed server seed does not equal the originally-published hash, the casino broke its commitment. Screenshot the seeds and contact support; serious operators treat this as critical.
Can I verify slot spins too?
Original provably fair slots can be verified the same way as Dice or Crash. Third-party slots from studios like Pragmatic Play use RNG certificates instead — see provably fair vs RTP.