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

eb7967d4aae1ca62ce86e49753e0e55fad2313271da11cec82bdd3ff2a1e736b

Seed

c76b599c3617450e91c642908442f1c3a5c0db0434c951026ab486ba21271577 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

5e5ba27c378c67cfd3590a5eae6662ca

Commitment

Batch 63,927, Merkle root 0d65ec3b1106a8d7d01641e894d58c84c1b2fd6ca0cb84ec0fafe87be8089191. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. e748df6938e2997eb4b1319026d9cd3ccc6ae10fd097a4175e19c378130e7760
2. bb53043c05b080f72d75d1307e25ce3bad5d934890dde5d949040216c7a6491a
3. c14ce72e0d05a5540fa0d0aae4565146eb4eac03fb54ce5672ed370732ec650d

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.