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

88f1df684250e90da93a80259ceeb9565512367d626aa3eeccf7266126ab9160

Seed

a65045506b7d5117f619474ef0c00c928f4c4859db8f0b0eae9a6892e592cd5a SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

0ef65cbf9f4c0aaf21f211997bc016a6

Commitment

Batch 54,202, Merkle root b756894ddfadba5904cb2aebeda94b6a5ade6ed902c460303fbeca77182d0449. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. fe6d02e4702241594214836c4dfb8bcb8f08b00b340f888493a7a6de71966cee
2. dd3aa452e0020c365708b1346a8443fdb0c590d7a8340e17372e65ab1fbeceb9
3. 702f3fb09bff8709fe99a0f62a3ae160e4a8bd1d0a0dfb0f4deeb301568f022b

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.