Don't trust — verify. This free tool lets you independently check any provably fair casino result using the exact same cryptographic algorithms the casino uses. Everything runs in your browser. Nothing is sent to any server.
Provably fair gambling uses cryptographic hash functions to guarantee that neither the casino nor the player can manipulate a game's outcome after the bet is placed. Every result is determined by three inputs that are locked in before the round begins.
Server Seed — A random string generated by the casino before the game. You see only its SHA-256 hash before betting. The actual seed is revealed when you rotate to a new seed pair, allowing you to verify all previous bets.
Client Seed — Your personal random string. You can set this to anything you want. This proves the casino cannot predetermine the outcome, because they don't control your input.
Nonce — A counter that increments with every bet. Combined with the seeds, this ensures each bet produces a unique hash even with the same seed pair.
Traditional online casinos ask you to trust that their random number generator is fair. Provably fair eliminates that trust requirement entirely. The cryptographic commitment scheme means the casino mathematically cannot change the result after you place your bet. If the revealed server seed doesn't match its pre-committed hash, the casino is provably cheating.
This system is standard at crypto casinos. The house edge is still built into how the hash converts to a game outcome, but each individual result is verifiably random and untampered.
Paste the values from your casino's provably fair settings. All computation happens locally in your browser using the Web Crypto API.
This process works for any provably fair casino. The specific UI locations vary, but the cryptographic verification is the same everywhere.
Before playing, find the server seed hash in the game's fairness settings. This is the casino's cryptographic commitment. Copy it and save it — this is your proof that the casino locked in their seed before your bet. The hash looks like: e3b0c44298fc1c149afbf4c8996fb924...
Most casinos let you set a custom client seed. Change it to something unique — your name, a random string, today's date. This proves the casino doesn't control all inputs. Also note the nonce (starts at 0 or 1 and counts up with each bet).
Place your bets normally. Each bet increments the nonce by 1. The game result is determined by: Hash(server_seed + client_seed + nonce). Keep track of which nonce corresponds to which bet if you want to verify specific rounds.
When you're ready to verify, rotate your seed pair. The casino will reveal the actual server seed for your previous session and generate a new hashed seed for the next one. You can now verify every bet from that session.
First, hash the revealed server seed with SHA-256 and confirm it matches the hash you saved in step 1. Then, enter the server seed, client seed, and nonce into our verifier tool to reproduce the game result. If the hash matches, the bet was fair.
The raw hash is converted to a game result using the first few hex characters. For example, for Dice: take the first 8 hex chars, convert to decimal, divide by 0xFFFFFFFF, and multiply by the roll range. Our tool shows these conversions automatically.