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

c560abe59c4f546521812ea5bb4cad01f0c7b188ac5649c1b4b86f11bb3943fb

Seed

eccdf0c3038ab24e389d1baf0cbc7185044a164b82811466fd8dcfff82e89692 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

793bbefdce7ca3f2044b26de4b7b64d6

Commitment

Batch 50,149, Merkle root 1b9fe692640cb72c482720c4e44884a9bf4c0c909f1ac39a7b84bc95a5d0afee. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 21b9ba6cbd5c511d5ee3b2c036dd83875aad1984cf5b937c44396cac93977ae5
2. a358395db0e24cc021af7fc3e1459460aa2866ccdb6a411e74c981e71a5ecaa3

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.