Provably fair - verify any round

Every Altenstar crash round is provably fair under the published altenstar-crash-v1 algorithm. Before a round opens, its seed is already committed: rounds consume seeds from a pre-generated reverse hash chain whose commitment was published before the chain's salt (a designated Bitcoin block hash) existed - so outcomes can be neither chosen nor reordered. After each round the seed is revealed and anyone can recompute the crash point below, in this browser.

Seed chains

Commitments are published before their salt block is designated (chain-before-salt).

Verify a round

Round ID

House edge (per game, published)

Max win multiplier

Verify

The math (run it yourself)

async function verifyCrashV1(serverSeed, salt, houseEdge, cap) {
  const enc = new TextEncoder();
  const key = await crypto.subtle.importKey(
    'raw', enc.encode(serverSeed), { name: 'HMAC', hash: 'SHA-256' }, false, ['sign']);
  const h = new Uint8Array(await crypto.subtle.sign('HMAC', key, enc.encode(salt)));
  // first 52 bits: 6 bytes + top 4 bits of the 7th
  const r52 = h.slice(0, 6).reduce((acc, b) => acc * 256 + b, 0) * 16 + (h[6] >> 4);
  const u = r52 / 2 ** 52;
  const raw = (1 - houseEdge) / (1 - u);
  return Math.min(Math.max(1.0, Math.floor(raw * 100) / 100), cap).toFixed(2);
}

Checks performed: SHA-256(server_seed) == server_seed_hash (the hash was public before any bet), the hash links into the seed chain, and the crash point equals the recomputation. P(crash ≥ m) = (1 - edge) / m; instant-bust probability equals the house edge; results are floored to cents and capped at the game's maximum multiplier.