SOLJackpot

Provably Fair

How It Works

SOLJackpot uses on-chain randomness to select winners. All game logic runs on the Solana blockchain, meaning the outcome is determined by verifiable on-chain data that cannot be manipulated by the house.

Winner Selection

The winner is selected using this algorithm:

  1. When the round countdown expires, the program reads the Solana SlotHashes sysvar for randomness.
  2. The random bytes are converted to a number: winning_number = random_u128 % total_pot
  3. Each player's deposit creates a range proportional to their contribution. The player whose cumulative range contains the winning_number is the winner.

Example

# 3 players deposit:

Player A: 1 SOL → range [0, 1,000,000,000)

Player B: 2 SOL → range [1,000,000,000, 3,000,000,000)

Player C: 1 SOL → range [3,000,000,000, 4,000,000,000)

# Random number generated:

winning_number = 2,345,678,901

# Result:

Falls in Player B's range → Player B wins!

Verification

Every round's random seed is stored on-chain in the GameRound account. You can verify any past round by:

  1. Finding the GameRound account for that round number
  2. Reading the random_seed field
  3. Applying the winner selection algorithm with the stored entries
  4. Confirming the result matches the stored winner

Important Notes

  • The current implementation uses Solana SlotHashes for randomness. For maximum security, this should be upgraded to Switchboard VRF (Verifiable Random Function).
  • The house rake is {2.5%} and is transparently deducted from each pot before payout.
  • All transactions are publicly visible on the Solana blockchain explorer.