How Provably Fair Works
Provably fair gaming uses cryptography to make it mathematically impossible for a casino to alter a game outcome after you've placed your bet. Here's exactly how it works — and how to verify it yourself.
The Three Ingredients
Every provably fair outcome is generated from exactly three inputs. Understanding them is the key to understanding the whole system.
Server Seed
A random string generated by the casino before the round. You receive a SHA-256 hash of it upfront — so the casino can't change it after you bet. After the round, the unhashed seed is revealed and you can confirm it matches the hash you were given.
Client Seed
A string you provide (or accept as randomly generated). Because the outcome depends on your client seed, the casino cannot pre-calculate what result a particular server seed will produce for you specifically.
Nonce
A counter that increments with every bet you place using the same seed pair. Bet #1 uses nonce 1, bet #2 uses nonce 2, and so on. This ensures every round produces a unique outcome even when seeds stay the same.
How Verification Works
The steps below are what the BonusReplay Verifier performs automatically when you enter your seeds.
Before you bet
The casino gives you the hashed server seed. This is your receipt — it proves the casino committed to a specific seed before you played.
You set your client seed
You provide your own string (or accept the randomly generated one). This is your input into the outcome formula.
The round plays out
The game outcome is computed from: HMAC-SHA256(server_seed, client_seed + ":" + nonce). The result maps to a game-specific output — a dice roll, card draw, mine positions, etc.
The server seed is revealed
When you rotate seeds, Stake reveals the unhashed server seed. You can SHA-256 hash it yourself to confirm it matches what you were shown upfront.
You can reproduce every outcome
With the revealed server seed, your client seed, and any nonce, you can recalculate the exact outcome of every round. This is what the BonusReplay Verifier does.
Why This Actually Matters
Traditional online casinos run on RNG software you can't inspect. You're trusting that the casino is honest and that their licensing body is checking. With provably fair gaming, you don't need to trust anyone — you can verify that the result you got is the mathematically correct output for your seed pair.
This doesn't change the house edge or improve your odds. But it does mean a rigged outcome is mathematically impossible without your client seed, which the casino doesn't know in advance.
Games Supported by BonusReplay Verifier
Verify your provably fair outcomes now
Enter your server seed hash, client seed, and nonce to reproduce any outcome — or scan thousands of nonces to find high-paying seed combinations.
Open Verifier Tool →