Provably-fair proof

This page reproduces the winner computation from public inputs. You can recompute every step in your browser's DevTools — don't trust our math, verify it.

1. Pre-commit (server_seed_hash)

Published when the lotto went live (2026-04-16T02:13:04.613Z).

289f2e765583f465255e82a92681873414b5b59ac0e1d00be1a844341c6a3bc5

2. Reveal (server_seed)

Revealed after draw (2026-04-17T05:10:27.100Z).

463a0851888164a3035c0173f449a3fbc3282d5455fe8babf1c677d7ad036acb

Hash check: ✓ sha256(server_seed) === published hash

3. Client seed inputs (all sold tickets)

#	Wallet	Winner?
1	did:pr...1fei
8	did:pr...v9ps	🎉
9	did:pr...1fei
14	did:pr...1fei
21	did:pr...1fei

4. Derived client_seed

client_seed = sha256(sorted by entry_number, joined as "N:wallet" with '|')

0ff4e198c3bad1d7c71e02a30c77fdfff010dc8aa77ae24640134f999b59c8ab

5. External entropy (Bitcoin block)

Mixed into the HMAC input so the draw depends on a value the operator could not have known when the server seed was committed ( 2026-04-16T02:13:04.613Z). Any Bitcoin block mined after the commit works — we take the tip at draw time.

sourcemempool.spaceheight945,434hash00000000000000000000306ae8c52159c39c0625f9aba6c595f2a03ade0baf31block time2026-04-17T05:08:09.000Z

Cross-check on mempool.space or blockstream.info.

6. Winner computation

HMAC-SHA256(server_seed, "client_seed:lotto_id:source:height:hash"), first 16 hex chars, mod sold_count (5).

hmac = a969acd46ead377defc204de01b74db4d1aa29d714a95a66916891e6ea4144c3

Computed index: 1 → winning entry: #8

7. Independent verification

Show JS snippet (paste into DevTools)

const seed = "463a0851888164a3035c0173f449a3fbc3282d5455fe8babf1c677d7ad036acb";
const hashStr = "289f2e765583f465255e82a92681873414b5b59ac0e1d00be1a844341c6a3bc5";
const clientSeed = "0ff4e198c3bad1d7c71e02a30c77fdfff010dc8aa77ae24640134f999b59c8ab";
const lottoId = "15ffb2c9-5d95-4fa5-adea-308404ac945d";
const sold = 5;
const entropy = "mempool.space:945434:00000000000000000000306ae8c52159c39c0625f9aba6c595f2a03ade0baf31";

async function run() {
  const enc = new TextEncoder();
  const seedBytes = enc.encode(seed);
  const hashed = await crypto.subtle.digest("SHA-256", seedBytes);
  const recomputed = [...new Uint8Array(hashed)]
    .map((b) => b.toString(16).padStart(2, "0")).join("");
  console.log("hashOk:", recomputed === hashStr);

  const key = await crypto.subtle.importKey(
    "raw", seedBytes, { name: "HMAC", hash: "SHA-256" }, false, ["sign"]
  );
  const message = entropy
    ? clientSeed + ":" + lottoId + ":" + entropy
    : clientSeed + ":" + lottoId;
  const sig = await crypto.subtle.sign("HMAC", key, enc.encode(message));
  const hex = [...new Uint8Array(sig)]
    .map((b) => b.toString(16).padStart(2, "0")).join("");
  const idx = Number(BigInt("0x" + hex.slice(0, 16)) % BigInt(sold));
  console.log("hmac:", hex);
  console.log("winnerIndex:", idx);
}
run();