Provably Fair Explained
Provably fair is a cryptographic system that lets you verify every casino game result is truly random and has not been tampered with. Unlike traditional casinos where you must trust the house, provably fair gives you mathematical proof of fairness. In this guide, we'll explain how it works, what terms mean, and how to verify results yourself. All definitions verified by our team of experts.
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🔐 VIEW CRYPTO CASINOS →How Provably Fair Works
Result = HMAC_SHA256(ServerSeed, ClientSeed + Nonce)
Server seed hash shown before play → actual seed revealed after
Client seed chosen by player → can be changed anytime
Nonce increments with each bet → ensures unique results
Server Seed
Generated by casino, kept secret until after play. Its hash is shown beforehand. After betting, casino reveals the actual seed for verification.
Client Seed
Generated by player (or casino with player input). You can change it anytime. Gives you control over randomness. Many use personal phrases.
Nonce
A counter that increases with each bet. Combined with seeds, it ensures each round produces a unique result even with same seeds.
Hash Function
SHA-256 creates a unique fingerprint of the server seed. You can verify the revealed seed matches the pre-shown hash, proving no tampering.
Provably Fair Example
| Component | Example Value | Purpose |
|---|---|---|
| Server Seed (hashed) | 7d2b8c9f1a3e5d7c9b2a4f6e8d1c3b5a7f9e2d4c6b8a0c3e5f7a9b1d3c5e7f9a | Shown before play to commit casino |
| Server Seed (actual) | a1b2c3d4e5f6g7h8i9j0k1l2m3n4o5p6q7r8s9t0u1v2w3x4y5z6 | Revealed after play for verification |
| Client Seed | myrandomphrase123 | Chosen by player, can be changed |
| Nonce | 42 | Bet number, increments each round |
| Result | 47.89 (dice roll) | Calculated from seeds + nonce |
How to Verify Provably Fair Results
Save Seeds Before Play
Note the server seed hash and your client seed before any bets. Take a screenshot for reference.
Play and Note Nonce
Each bet has a nonce (bet ID). Record which nonce corresponds to the round you want to verify.
Get Revealed Seed
After playing, the casino reveals the actual server seed in your bet history or fairness section.
Use Verifier Tool
Enter server seed, client seed, and nonce into the casino's verifier or an independent tool.
Compare Results
If calculated result matches what you saw, the game was fair. If not, contact support immediately.
Key Provably Fair Concepts
Why Provably Fair Matters
Traditional casinos use closed RNGs you must trust. Provably fair gives mathematical proof. Essential for crypto casinos without traditional regulation. Casino safety guide →
Changing Client Seed
Most casinos let you change your client seed anytime. Some recommend changing periodically for security. Use random strings or let casino generate.
Hash Verification
Before play, you see SHA-256 hash of server seed. After play, casino reveals actual seed. Hash the revealed seed — it must match the pre-shown hash. If not, casino cheated.
Provably Fair Games
Common: dice, crash, blackjack, roulette, slots. Any game can be provably fair. Check game rules for verification instructions. Game guides →
Third-Party Verifiers
Use independent tools to verify results, not just casino's own verifier. Multiple tools ensure accuracy. Our verifier supports major algorithms.
Limitations
Provably fair verifies individual rounds, not overall RTP. Casinos can still have high house edge. Always check game RTP alongside fairness. RTP explained →
❓ Frequently Asked Questions
What is provably fair?
Provably fair is a cryptographic algorithm that allows players to verify each game result is fair and has not been tampered with. It uses hashing and seeds to prove the casino didn't manipulate outcomes. Common in crypto casinos.
How does provably fair work?
The casino generates a server seed and provides its hash. The player generates a client seed. Both combine to create a game result. After the game, the casino reveals the original server seed, allowing the player to verify the result using the same algorithm.
What is a server seed?
A server seed is a secret string of characters generated by the casino. Its hash is shown before play, but the actual seed is revealed after. Used with client seed to determine game outcomes.
What is a client seed?
A client seed is generated by the player (or casino with player input) and can be changed anytime. It ensures the player has influence over the randomness. Many players use personal phrases or random generators.
What is a nonce in provably fair?
A nonce is a counter that increments with each bet. Combined with seeds, it ensures each game round produces a unique result even with the same seeds. Prevents predictability.
How do I verify provably fair results?
After playing, the casino reveals the server seed. Use an online verifier or casino's tool to input server seed, client seed, and nonce. The tool recalculates and confirms the result matches what you saw. Try our verifier →
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