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

733ea0b9199d45b79dae754d52615b29e848d1ec2033c9989263aa24094fd632

Seed

336662aff5c2321d0a7db6fd7f557fbab4d9dfce69caeccf094a289bd10bedca SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

b83cb5c6f8270e4b552fe8a82caa80e6

Commitment

Batch 48,983, Merkle root 7ea9b44f67e5ce1fec4f75d2d6913cd3026b73945bbf2a2101cd6d84f4b03078. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 5a833b4a70b6c32ff6a83219e9f3984e996a7982186deba3b678ba4c24ac93f4
2. 636363dde5c0d2ba2652fe08ab5c6bceb58fa5c2fcd077cd678118200f481745
3. 84ea9e3fc4a79779061b7c7c51324e74b45a0c14d7a558dc05c69200469bb135

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.