Blackjack

Provably fair

Verify fairness

The session's seed decides every card. Its hash was committed before the first hand; the seed is revealed when the session ends. Each round's cards come from HMAC-SHA256 keyed by the seed over the round's number and the bettor's own seed.

Seed hash

6149e4a2ac50b04aa1436923b6da52ec098779bf92e25099ee410bebeb344188

Seed

27342eca7bdd49fb7448df454b627ebbd5893ca2c692430c6c763e7b2213c654 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

59167f6519e0a5947044e8217d2842fb

Commitment

Batch 67,692, Merkle root 37b9d4a2829240e073611b37bb48c89fd47ab55c34758c751b56817a5ce9c26a. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 47bc06d3771659be3f08270a220f233908f5ec5ccb1f66e4f9e4dd36b8604ae5
2. 7f63a7cd59d4eb100f851e266b517637111488a6febbe60db7d343e91f00c7c5
3. 2840e8b31dcfdf6db2fe447cdf785a6ec941d95e1628d49052de874d2bcf9c11

Checked: the seed hash proves into the root.

To check it yourself, take the session's proof:

1. Hash the seed as above and compare it with the seed hash; prove the seed hash into the root with the Merkle path (keccak256, as for every match).
2. For each round: round seed = HMAC-SHA256(key = seed, "degen.house.round.v1" ‖ 0x00 ‖ u64be(length of the bettor's seed) ‖ bettor's seed ‖ u64be(round)).
3. Key ChaCha20 (RFC 8439, zero nonce) with the round seed and read little-endian 64-bit words; a card is the next word below 2⁶⁴ − 1 − ((2⁶⁴ − 1) mod 52), modulo 52.
4. Replay the round's actions with the game's rules: the cards and the payout must match.

The replay plays every hand rebuilt this way on the server from the same data, and marks any that does not rebuild as recorded.