How Does Aviator's Provably Fair System Actually Work?

Provably Fair is the cryptographic system that separates Aviator from traditional casino games where you simply "trust" the operator. It allows any player to independently verify that each round's crash multiplier was determined before bets were placed and was not manipulated. This guide explains exactly how the system works, provides verification code, and includes an interactive tool to check any round yourself.

What Problem Does Provably Fair Solve?

In a traditional online casino, you bet and hope the software isn't rigged. There's no way to verify. The casino says "trust us" and points to a gambling license — but licenses verify business practices, not individual game outcomes.

Provably Fair eliminates this trust requirement using the same cryptographic principles that secure Bitcoin, HTTPS, and digital signatures. The system guarantees two things:

1. Pre-determination: The crash point is calculated before any bets are placed. The casino commits to the result cryptographically.
2. Verifiability: After the round, you can independently recalculate the crash point using publicly revealed data. If your calculation matches, the round was fair.

This works because of a mathematical property of cryptographic hash functions: they are one-way. You can easily compute the hash of any input, but given only the hash, finding the input is computationally impossible — it would take all the computers on Earth billions of years.

How Does the SHA-256 Hash Commitment Work?

The hash commitment is the mechanism that prevents the casino from changing the outcome after seeing your bet. Here's the sequence:

If the hashes match, the server seed was not changed after bets were placed. If they don't match, the casino cheated — and this would be publicly provable.

"The hash commitment scheme is the same cryptographic primitive used in Bitcoin mining, TLS certificates, and digital signatures. It has been studied and attacked by the world's best cryptographers for decades. No one has broken it."

How Is the Crash Point Calculated?

Once the server seed, three client seeds, and nonce are determined, the crash point is derived deterministically. The calculation uses SHA-512:

// Inputs
combined = server_seed + client_seed_1 + client_seed_2 + client_seed_3 + nonce

// Step 1: Hash with SHA-512
hash = SHA-512(combined)

// Step 2: Take first 8 hex characters (32 bits)
hex_segment = hash[0:8]

// Step 3: Convert to integer
int_value = parseInt(hex_segment, 16)

// Step 4: Apply crash formula with 3% house edge
// If int_value == 0, crash at 1x (instant crash)
// Otherwise:
raw_multiplier = (2^32) / (int_value + 1)
crash_point = max(1.00, floor(raw_multiplier * 97) / 100)

The × 97 / 100 factor is where the 3% house edge lives. Without it, the game would be perfectly fair (0% edge). With it, approximately 3% of the time the crash point is forced to 1.00x (instant crash), ensuring the house retains 3% of all wagered money over time.

The key insight: the same inputs always produce the same crash point. Anyone with the inputs can verify the output. The randomness comes from the server seed (unknown before the round) and client seeds (contributed by independent players).

How to Verify a Round (Step by Step)

You can verify any Aviator round — past or present. Here's how:

1. Open the game history. In Aviator's interface, click the history icon (clock symbol) to see past rounds.
2. Select a round and note these values:
   • Server Seed (revealed after round ends)
   • Server Seed Hash (shown before the round started)
   • Client Seed 1, Client Seed 2, Client Seed 3
   • Nonce (round number)
   • Crash Point (the actual result)
3. Verify the hash commitment. Compute SHA-256(Server Seed). It must match the Server Seed Hash. If it doesn't, the round was tampered with — report it immediately.
4. Recompute the crash point. Use the algorithm above with all the seeds and nonce. Your result should match the actual Crash Point ± rounding.

Use our interactive tool below or the code examples to perform these calculations.

Interactive Hash Verification Tool

Verification Code Examples

You don't need to trust our tool — here's how to verify using standard tools on your own computer.

Command Line (Linux/Mac)

# Step 1: Verify hash commitment
echo -n "a3f8b2c1d9e6f7a0" | shasum -a 256
# Output should match the pre-round hash

# Step 2: Calculate crash point
COMBINED="server_seedclient1client2client3nonce"
HASH=$(echo -n "$COMBINED" | shasum -a 512 | cut -d' ' -f1)
HEX=${HASH:0:8}
echo "First 8 hex chars: $HEX"
INT_VAL=$((16#$HEX))
echo "Integer value: $INT_VAL"
# Apply crash formula in Python (bash can't handle the precision)
python3 -c "v=$INT_VAL; print(max(1.0, int((2**32/(v+1))*97)/100))"

JavaScript (Browser Console)

// SHA-256 hash verification
async function verifySeed(serverSeed, expectedHash) {
    const encoder = new TextEncoder();
    const data = encoder.encode(serverSeed);
    const hashBuffer = await crypto.subtle.digest('SHA-256', data);
    const hashArray = Array.from(new Uint8Array(hashBuffer));
    const computed = hashArray.map(b => b.toString(16).padStart(2, '0')).join('');
    return computed === expectedHash.toLowerCase();
}

// Usage:
verifySeed('a3f8b2c1d9e6f7a0', 'expected_hash_here')
    .then(match => console.log('Hash matches:', match));

Python

import hashlib

def verify_hash(server_seed: str, expected_hash: str) -> bool:
    """Verify SHA-256 hash commitment."""
    computed = hashlib.sha256(server_seed.encode()).hexdigest()
    return computed == expected_hash.lower()

def calculate_crash(server_seed: str, client1: str,
                    client2: str, client3: str, nonce: int) -> float:
    """Calculate crash point from seeds and nonce."""
    combined = f"{server_seed}{client1}{client2}{client3}{nonce}"
    hash_hex = hashlib.sha512(combined.encode()).hexdigest()
    hex_segment = hash_hex[:8]
    int_value = int(hex_segment, 16)
    if int_value == 0:
        return 1.00
    raw = (2**32) / (int_value + 1)
    crash = max(1.00, int(raw * 97) / 100)
    return crash

# Example usage:
print(verify_hash('a3f8b2c1d9e6f7a0', 'your_expected_hash'))
print(calculate_crash('server', 'client1', 'client2', 'client3', 12345))

Understanding the Probability Formula

The Provably Fair algorithm produces crash points following a precise mathematical distribution. The probability of the game reaching any multiplier m is:

This formula has verifiable implications:

You can test this distribution yourself: collect 1,000+ round results from the game history and compare the observed frequencies to the formula predictions. They will converge. Our bankroll calculator uses this exact formula for all its calculations.

What Provably Fair Does NOT Guarantee

Provably Fair is powerful, but it's important to understand its boundaries:

• Does NOT eliminate the house edge. The 3% edge is built into the formula. Provably Fair ensures the edge is exactly 3%, not more.
• Does NOT guarantee you'll win. Each round is independent. Variance means you can have long losing streaks that are mathematically expected.
• Does NOT prevent the casino from refusing payouts. Provably Fair verifies game outcomes, not business practices. A casino could still refuse withdrawals for unrelated reasons.
• Does NOT apply to non-Provably Fair games. Traditional slots and table games at the same casino may not offer this verification.
• Does NOT mean the RNG is perfect. The system is only as strong as its implementation. Bugs in the code could theoretically compromise fairness, though the algorithm itself is sound.

For a complete analysis of what the house edge means for your bankroll, see our strategy analysis and bankroll calculator.

Provably Fair FAQ

Want to understand how scammers falsely claim to "crack" this system? Read our predictor scam exposé. For practical playing advice based on the math, see our strategy guide.