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

27c51baae9b175d404ffa04ce3ae45c5ba4ff1714ac84bfa1e808e588d87cf07

Seed

6036d6f63b9448053afd7fd5ca5c9f4883f29070c9e3bef8502b07c771e2999d SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

fe6e7a6bba6ab0486ef18bb59cb0ab0c

Commitment

Batch 73,527, Merkle root f93eaf87f4682398c833f28a605c9649e592c76253ffe50c505718fbc9ecdb7f. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. b5bd9918fd7b62c70d7d645b8bc33340b327a2f7967f136886013d6533b4c6a5
2. 14f4f8c17935229ba3653e41643c73e77d0d84050fe70957ba4cdf0679c4aef5

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.