Provably Fair: Trust, But Verify

The days of "black box" algorithms are over. Every bet on Duel Casino can be cryptographically verified by you, ensuring absolutely zero manipulation.

What is Provably Fair?

Provably Fair is a system based on open-source cryptographic algorithms that allows players to verify that the outcome of a game was predetermined and not manipulated after the bet was placed.

Duel uses standard HMAC_SHA256 hashing to generate game results. This means the result is math, not magic.

How It Works (The 3 Variables)

1. Server Seed

Generated by the casino. It is hidden (hashed) before you bet, so you know we can't change it, but we can't change the outcome to beat you.

2. Client Seed

Generated by YOU (or your browser). This ensures the casino doesn't know the final input variables when generating the result.

3. Nonce

A simple counter (1, 2, 3...) that increases with every bet you make, keeping each round unique.

Step-by-Step Verification Guide

  1. Before Betting: You can see the Hashed Server Seed in your fairness settings. This is the "commitment" from the casino.
  2. Place Your Bet: The game result is calculated using: HMAC_SHA256(ServerSeed, ClientSeed + Nonce).
  3. After Betting: You can "rotate" your seed. This reveals the previous Un-hashed Server Seed.
  4. Verify: Copy the revealed seed into any third-party hash verifier (or use the code below). If the hash matches the one shown before the bet, the game was 100% fair.

Verification Code Example (Node.js)

Duel provides the source code for verification. You don't have to take our word for it—run the code yourself.

const crypto = require('crypto');

const serverSeed = 'your_revealed_server_seed';
const clientSeed = 'your_client_seed';
const nonce = 1;

const hash = crypto.createHmac('sha256', serverSeed)
                   .update(`${clientSeed}:${nonce}`)
                   .digest('hex');

console.log(`Game Result Hash: ${hash}`);
// This hash determines the roll number (e.g. 0-100 on Dice)

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