Provably Fair Verifier

What this tool actually checks

A provably fair casino game uses a commit-reveal pattern: before play, the operator publishes SHA-256(server_seed) as a public hash. After you rotate your client seed, the operator reveals the previous server_seed. You verify that SHA-256(revealed_seed) matches the published hash — if it does, the operator could not have substituted the seed after seeing your bets.

The outcome itself is computed via HMAC-SHA-512(server_seed, client_seed:nonce). The resulting 128-character hex string is sliced into 5-character chunks, each interpreted as a decimal in [0, 1) and then mapped to the game-specific outcome.

Three things provably fair does NOT prove

• House edge.Provably fair verifies the RNG. It does not change the operator's payout math. A dice game with a 1% house edge is still 1% house edge — the cryptography just proves the outcome wasn't hand-picked.
• Display honesty.The game might show you "near miss" animations, but the cryptographically-determined outcome was decided the instant you clicked bet.
• Operator solvency.Provably fair tells you the math is right; it doesn't tell you the operator will pay your withdrawal.

Try the demo first, then verify a real bet

The default preset uses a known seed pair so you can see the full flow. To verify a real bet, paste the values from your casino's provably fair page (usually under Account → Fairness or similar). Stake.com, BC.Game, Rollbit, and most major crypto casinos publish these values directly. Read the full provably fair master guide →

Frequently asked questions

Why are there 8 rolls per HMAC?

The HMAC-SHA-512 output is 128 hex chars = 25 × 5-char rolls. The convention from Stake.com's original spec is to expose the first 8 rolls per HMAC call — enough for most game modes. After 8 rolls, the nonce increments and a fresh HMAC is computed.

Is the cryptography here actually secure?

SHA-256 is a NIST FIPS 180-4 standard with no known practical collisions. HMAC-SHA-512 is RFC 2104. The Web Crypto API in modern browsers ships these directly — no JavaScript reimplementation. We don't add any custom logic that could weaken them.

Will Wild Fortune work with this tool?

Mostly no. Wild Fortune's main library uses audited RNG (Itech Labs / eCOGRA-style monthly attestations) rather than provably fair primitives. A small subset of Plati+ live games references blockchain hashes but doesn't expose the full commit-reveal flow. For provably fair, look at dedicated crypto casinos covered in the AU crypto guide and CA crypto guide.

18+ only. Provably fair verifies the RNG, not the house edge. Gambling involves real financial risk. Safer-gambling resources.