Provably fair Blackjack verifier

Recompute any Blackjack round from the revealed server seed, your client seed and the nonce. House edge: ~0.5% with basic strategy.

The entire shoe (1–8 decks) is shuffled with committed floats before the hand. Your two cards, the dealer's two, and every hit card come from fixed positions in that shoe.

This is the strongest form of provable fairness in card games: the dealer cannot pull a different card in response to your decision.

Odds and payouts

With perfect basic strategy the edge is about half a percent; side bets carry much more.

How to verify a blackjack round yourself

  1. Rotate or end the seed pair in your account so the casino reveals the server seed it committed to. Until that happens the hash is a promise, not a proof.
  2. Copy the revealed server seed, your client seed and the nonce of the round you want to check — the nonce is the round counter, not a timestamp.
  3. Paste all three into the verifier above. It recomputes the HMAC chain and derives the blackjack outcome the same way the operator's server did.
  4. Compare the result with what your bet history shows. A mismatch on any single round is the only evidence of tampering that actually means something.
  5. Check the committed hash too: hash the revealed server seed and confirm it equals the hash the casino published before you played.

Verification proves the result was not changed after you bet. It does not make blackjack profitable — the ~0.5% with basic strategy house edge is applied openly, in the payout table, and it is unaffected by any of this.

Frequently asked

The shoe shows different cards than I got — why?

Multi-seat tables consume cards for other players too. Verify from the nonce of your hand and walk the shoe forward — your cards appear at the positions the seats before you left them.

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