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

8804e21de6684b5ee215d5d74c79d55270f79928dc954323c81c21e0288ac721

Seed

58fe9d1967f229dab47e9e2b7736891cbb1fbdc025214794e62f506cf9cf5e7c SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

f59a7721669eb5fb8cc6f35dc6220e86

Commitment

Batch 61,423, Merkle root 74d04ec32a1671fb5ba1ae0cf95405080c796446ec0f09b23bf3a87d543bada1. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. e3480936084d898d4fb1e72e394c427551cb61d03db44f2eb53392d98c27ba75
2. 8684e89b070da9ff5914cdb4ed9698d3877851dc156b34883dbd630a13d657ed
3. 8df838cdc4a25c187852ca4fc056fe2d5a4d934aff9dad3f9a08a87f5e05e00a

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.