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

fe1c946cc81864c848cee38c798dd308a24150b57dfda7ff66512e94171eec1f

Seed

deac3b5b3515733186d808afa530782b014235e1ad646536ed660ed64ef86f30 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

64877ad2636ace6e38f94ab15c58e3e8

Commitment

Batch 59,242, Merkle root d74e1ea8dfab2eccd2d84ed96437cd673aca0c43457d9fec6f6e2ad96a94054c. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 41a2a7d717a8a92c9c28689be03e0d7dbd189b23ea5413d5cf5f13510fa501be
2. d0d9f34b18f0fc72a348d5d6a4003be73083fb49cf9eefff4616856001152d5d

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.