Trust the maths, not us
Every round on a Haddzy original locks its outcome to a server seed published before play and a client seed you control. After the round, both seeds are revealed — anyone can re-derive the result and confirm we didn't move it.
What it is
Every round is worked out from three things committed before you press the button: our secret seed, published as a fingerprint; your own seed; and a counter. We can’t re-roll it, and we can’t pick a seed to suit your bet after seeing it.
Haddzy originals, cases, slots, battles and raffles all run on the same commitment scheme. The algorithm is published, and the check runs in your browser — nothing you type is sent to us.
How seeds work
Our half. We publish its SHA-256 fingerprint before your first bet on it and reveal the seed itself when you rotate. Hash the revealed seed yourself — it has to match the fingerprint we posted, or we changed it.
Your half. Set it to anything: a word, a date, the last round’s hash. Change it whenever you like — it applies from your next bet and never touches a round already running.
A counter that goes up by one with every bet on the pair, so the same two seeds never build the same round twice. Your bet history carries the nonce for each round.
Verify a round
The fairness panel on every game holds your seeds alongside the round you just played and the fingerprint we committed to.
Rotating reveals the server seed you have been playing on and swaps in the one we already committed to. Everything played on the revealed seed stays checkable forever.
The verifier rebuilds the round in your browser from the revealed server seed, your client seed and the nonce — the same code our server runs.
The revealed seed must hash to the fingerprint we published, and the numbers must land where your round landed. If either misses, tell us.
Per-game notes
Mines, Keno, Dice, Plinko, Coinflip, Blackjack and friends use your own seed pair — check any of them from your bet history once you rotate. Crash and Roulette are the exceptions: everyone in the round shares one seed — crash off a hash chain committed long before it runs, roulette off a per-spin seed revealed the moment it settles.
Same seed pair, but the number it produces is looked up in a published weight table. A slot round verifies against the exact version of the table it was played on, so an updated table never rewrites your history.
A shared round can’t lean on one player’s seed, so it mixes in a public randomness beacon — a future drand round or blockchain block id — committed before that value exists. Seeds and beacon are shown once the battle settles.
Winners come from a server seed committed when the raffle opens plus that same kind of public beacon. The whole draw — tickets, seeds, beacon — is published moments after it runs, so anyone can replay the pick.
