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

46c9dfe7532164a5c1c842374494db9872f100d1f0d43e34b9ddec49711e51f5

Seed

ab53ea7b73a4577c6a5de60496e599849141b0c8de5c3547bfd88a209f439aa3 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

27c3551490eee2cdc0844c6fbf0e415f

Commitment

Batch 64,691, Merkle root 36f300829a9207ec7c097ad8d8fe3e6cf6718315634bfcd4eec75f25bb73d4d6. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 758352c7f92882422fccb45c873d3d86c774cfe3e8d9f5df2ed7ca140629362f
2. 827ba4d4c1a00ee00bb78276a827d048c519e88fe1daba095b73c15c2c22ba4e
3. 78e0d6adbe9b8695a73155b9fe54dbc5a7fd692520de79d0cf700108ca230dfd

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.