Understanding the cryptographic magic that ensures casino games are fair
In traditional online casinos, you have to trust that the casino isn't manipulating game results. But how can you be sure? You can't see the code, you can't verify the randomness, and you have no way to prove if you were cheated.
Traditional casinos: "Trust us, we're fair!" 🤷
Provably fair uses cryptography to create a system where:
Provably fair casinos: "Don't trust us, verify us!" ✅
Before you place your bet, the casino generates a random string called the Server Seed.
The casino keeps this SECRET but shows you a hash (encrypted fingerprint) of it:
This hash is like a locked box - it proves what the seed is without revealing it. The casino CANNOT change the seed now without you knowing.
You can set your own Client Seed to any string you want. This ensures YOU have influence on the outcome.
The casino can't predict the result because they don't control your seed. You can change it anytime!
The casino combines the Server Seed + Client Seed + Nonce (bet number) and runs it through a cryptographic algorithm:
This generates a number that determines your game result (dice roll, crash point, card dealt, etc.)
After the bet, the casino reveals the original Server Seed. Now you can verify:
Check 1: Verify the hash matches
Check 2: Recalculate the result
✅ PROVABLY FAIR - The casino didn't cheat!
Here's a real example you can verify yourself:
Copy these values into our verification tool to see if the casino was honest!
Verify This BetDice
const result = hmacSHA256(serverSeed, clientSeed + '-' + nonce)
const diceRoll = (parseInt(result.substring(0, 8), 16) / 0xffffffff) * 100Crash
const hash = sha256(serverSeed + clientSeed + nonce)
const crashPoint = calculateCrashPoint(hash)Slots
const result = hmacSHA256(serverSeed, clientSeed + nonce)
const reelPositions = convertToReelPositions(result)By showing you the hash before the bet, the casino locked in their server seed. They can't change it without the hash being different.
Your client seed influences the outcome. The casino can't predict the result because they don't control your seed.
The same inputs always produce the same output. You can verify the calculation yourself or use our tool.
SHA-256 and HMAC are industry-standard algorithms used by banks and governments. They're mathematically proven to be secure.
No. Once they show you the hash of the server seed, they're locked in. If they change the seed, the hash won't match and you'll know they cheated.
Not necessarily. You can spot-check random bets or use our bulk verification tool to check many bets at once. If a casino is cheating, it will show up in the pattern detection.
That's what our tool is for! You don't need to understand the cryptography - just paste your bet details and we'll verify it for you. The math is open-source so anyone can audit our tool.
No. Only casinos that implement provably fair algorithms can be verified. Most major crypto casinos (Stake, BC.Game, Rollbit, etc.) are provably fair, but always check before playing.
Yes! Our algorithms are open-source and match exactly what the casinos use. We have no incentive to lie - we're not the casino. Plus, the community can verify our verifications.
Use our tool to verify any bet from any provably fair casino
Start Verifying Now