Provably Fair

How a round is committed

1. The server generates a 32-byte random serverSeed and publishes only its SHA-256 hash before the round starts. The seed is hidden until reveal.
2. The challenger's join transaction confirms on Solana, fixing a targetSlot = currentFinalizedSlot + 5.
3. Once targetSlot is finalized, its blockhash becomes the publicSeed — a public, immutable, untouchable input.
4. Outcome is derived from SHA-512(serverSeed | publicSeed | gameId); first 16 hex chars taken as a 64-bit BigInt, modulo the ticket range. Coinflip uses ticket < 500,000 → HEADS.
5. At reveal, the server publishes serverSeed and the blockhash it used. Anyone can re-run the SHA-512 themselves with the data below.

House fee

The house takes 5% of the WINNINGS — that is, 5% of the amount the winner gains. Both players wager X. The winner takes the pot (2X) minus a 5% fee on their gain (5% of X). Winner receives 1.95X; net gain is 0.95X.

Example: Both players wager 0.01 SOL. Pot = 0.02 SOL. Fee = 0.0005 SOL (5% of 0.01). Winner receives 0.0195 SOL. Net win is +0.0095 SOL.

Reference snippet

Use this Node script to verify any resolved round. The result must match resultHash and ticket published on the room.

import crypto from 'crypto';

function compute(serverSeed, publicSeed, gameId) {
  const hash = crypto.createHash('sha512')
    .update(`${serverSeed}-${publicSeed}-${gameId}`)
    .digest('hex');
  const uint = BigInt('0x' + hash.slice(0, 16));
  const ticket = Number(uint % BigInt(999_999 + 1));
  return { hash, ticket, side: ticket < 500_000 ? 'HEADS' : 'TAILS' };
}

Verify a round in-browser

Paste the serverSeed, publicSeed, and gameIdfrom any revealed room and we'll re-compute the hash + ticket using the same algorithm. If it matches what's shown on the room card, the outcome is verified.