ApeCharts.com Game Verification

How Provably Fair Works

ApeCharts.com uses a provably fair system to ensure game outcomes cannot be manipulated:

1. Before each game: The server generates a random server seed and publishes only its hash (the server seed hash).
2. During the game: The outcome is determined by combining the server seed with the game ID.
3. After the game ends: The server reveals the original server seed.
4. Verification process:
   • First, you can verify that the revealed server seed matches the pre-published hash by using the SHA-256 algorithm.
   • Second, you can use this tool to independently calculate the game outcome using the revealed server seed and game ID.
   • If both checks pass, this proves the game outcome was predetermined and not manipulated.

Why Wait for the Server Seed?

The server keeps the actual server seed secret during the game and only reveals it after the game ends. This prevents anyone (including the operator) from knowing the outcome in advance, while still allowing for verification afterward.

Source Code

To ensure transparency, the verification algorithm matches exactly what's used on the server. You can review the key portions of the code below:

// Price drift calculation
function driftPrice(
    price,
    DRIFT_MIN,
    DRIFT_MAX,
    BIG_MOVE_CHANCE,
    BIG_MOVE_MIN,
    BIG_MOVE_MAX,
    randFn,
    version = 'v2',
    STARTING_PRICE = 1.0
) {    
    let change = 0;
    
    if (randFn() < BIG_MOVE_CHANCE) {
        const moveSize = BIG_MOVE_MIN + randFn() * (BIG_MOVE_MAX - BIG_MOVE_MIN);
        change = randFn() > 0.5 ? moveSize : -moveSize;
    } else {
        const drift = DRIFT_MIN + randFn() * (DRIFT_MAX - DRIFT_MIN);
        
        // Version difference is in this volatility calculation
        const volatility = version === 'v1' 
            ? 0.005 * Math.sqrt(price)
            : 0.005 * Math.min(10, Math.sqrt(price));
            
        change = drift + (volatility * (2 * randFn() - 1));
    }
    
    let newPrice = price * (1 + change);

    if (newPrice < 0) {
        newPrice = 0;
    }

    return newPrice;
}

// Game verification function
function verifyGame(serverSeed, gameId, version = 'v2') {
    const combinedSeed = serverSeed + '-' + gameId;
    const prng = new Math.seedrandom(combinedSeed);
    
    let price = 1.0;
    let peakMultiplier = 1.0;
    let rugged = false;
    
    for (let tick = 0; tick < 5000 && !rugged; tick++) {
        if (prng() < RUG_PROB) {
            rugged = true;
            continue;
        }
        
        const newPrice = driftPrice(
            price,
            DRIFT_MIN, 
            DRIFT_MAX, 
            BIG_MOVE_CHANCE, 
            BIG_MOVE_MIN, 
            BIG_MOVE_MAX,
            prng.bind(prng),
            version
        );
        
        price = newPrice;
        
        if (price > peakMultiplier) {
            peakMultiplier = price;
        }
    }
    
    return {
        peakMultiplier: peakMultiplier,
        rugged: rugged
    };
}