Blackjack
Verify any Duel Blackjack deal. Each of the next 50 cards is drawn independently from HMAC-SHA256 at cursor 0..49 — uint32 modulo 52 picks a card from the standard deck. Not a Fisher-Yates shuffle: by design, the same card can repeat in the stream.
Frequently asked
Is Duel Blackjack really provably fair?⌄
Yes. Duel publishes a cryptographic commitment (the hash of the server seed) for each round BEFORE you bet. Afterwards the server seed is revealed and anyone can recompute the outcome — which is exactly what the verifier above does. If the computed result matches the shown one, the round wasn't manipulated.
How do I verify a Duel Blackjack round?⌄
Paste the revealed server seed, your client seed and the bet nonce into the form above. The verifier re-runs the official math and shows you the exact result, step by step. Everything runs in your browser — your seeds never leave the device.
Where do I find my Duel seeds?⌄
On your Duel account's fairness / seed page. There you can rotate the server seed: rotating reveals the old one (so you can verify all your previous bets) and commits a fresh hash for the next ones.
Can Duel cheat on Duel Blackjack?⌄
Not without getting caught. The server-seed hash is published before the bet, so Duel can't change the seed after the fact — any change would produce a different hash than the committed one. That's what makes the game verifiable.