THE RAFFLE FAIRNESS · DRAW #315

Commit. Reveal. Recompute.

The operator cannot bias which holder wins. The server seed is committed before the window closes; the roll is HMAC-SHA-256 of the resolved slot hash keyed by that seed, walked over the weighted holder snapshot. Recompute it here and check the winner yourself — we never ask you to trust our outcome flag.

Drawn Pot 28 cards · $5,519Holders 2,836Outcome WONRaw draw id 369

FOUR STEPS · ONE VIEWPORT

Commit > Snapshot > Reveal > Roll

Commit
SHA-256 of the server seed lands before the window closes
A 256-bit server seed is generated and its SHA-256 hash is committed before the target slot resolves. The operator cannot swap the seed once the slot is known.
serverSeedHash = SHA-256(serverSeed)
Snapshot
Every holder balance is recorded at the close slot
When the window closes we record a Merkle root of every eligible $GACHA balance at that exact Solana slot. Nobody touches your balance — we just take a tamper-evident snapshot the weighted pick runs over.
snapshotMerkleRoot = MerkleRoot(holders[closeSlot])
Reveal
We publish the seed + the resolved slot hash
Once the target slot lands we reveal the serverSeed and the resolved slot hash. Anyone hashes the seed to confirm it matches the commit, then feeds the slot hash into the roll.
reveal: serverSeed ‖ slotHash
Roll
HMAC-SHA-256 picks the weighted winner
roll = HMAC(seed, slotHash ‖ utf8(drawId)), mapped into [0,1). We walk the prefix-sum of weights — first holder whose slice covers the offset wins the whole pot.
roll = HMAC(seed, slotHash ‖ drawId)

SECTION 02

Recompute the roll. Right here. In your browser.

The widget re-runs the same HMAC-SHA-256 the worker ran, confirms the revealed seed hashes to the pre-window commit, and compares the published roll. If our published roll diverges from what your browser computes, the badge turns red.

Recomputing draw #369 in your browser…

The pot28 cards · $5,519 — winner takes all

28 cards worth $5,519 opened this window — 4Ye9…KUaW held 0.11% of the eligible snapshot and won the pot.

The winnerSolscan

4Ye9…KUaW

Slabs airdropped straight to the winner's wallet.Airdrop 5zqE…HiM4

Win chance: 0.11%
About 1-in-N: 872
Winner balance: 1,022,268 GACHA
Eligible pool: 890,890,437 GACHA

REFERENCE IMPLEMENTATION

Copy-paste. Run it locally. Same answer.

raffle-roll.tsTypeScript

import { createHmac } from 'node:crypto';

// Mirrors the draw-runner's roll derivation.
export function raffleRoll(
  serverSeedHex: string,
  slotHashHex: string,
  drawId: number,
): string {
  const mac = createHmac('sha256', Buffer.from(serverSeedHex, 'hex'));
  mac.update(Buffer.from(slotHashHex, 'hex'));
  mac.update(Buffer.from(String(drawId), 'utf8'));
  return '0x' + mac.digest('hex');
}

// Map the roll into [0,1), then walk the holder snapshot's weight
// prefix-sum (sorted by address, Merkle-committed) — the first holder
// whose cumulative slice covers the offset wins the whole pot.

Node ≥ 20 · no dependencies · same output as the browser widget.

Raw draw id 369 — what the proof and this URL key on.Missing rows land once the draw reveals. Very early draws predate parts of this record — what exists is shown, nothing is backfilled.This draw in history How the mechanism works