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

4acb2bb9cba7af9698b023687c907c81046cd9b23b6bc4c403439959a02fd6d0

Seed

6858b63d095b87458eae2c9cfac64ee643470f283ba07fef2d19744243e0545d SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

99ea686de8735e5d0d861353e39e2a14

Commitment

Batch 61,641, Merkle root 1997aadb3e6493894cb2dcdc25749075425b9164b20e22f65b5804f20c1fac99. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 8497cdf6a7fc57c0a09c8d0f541fc5bb7f08004192a34ca7a77d60b39843fdbf
2. c540c613dc584376aecb94040de2158dd70575f09d7009621fe6648f23ba99ae
3. a5a4215d223cd263cf46ba020de316b67444588e8e89e2d3d24110fb8fa9a53c

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.