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

5ec9408ac76fddc0261db6450775418272f18ca0596f94c06b1b93718b8d4da2

Seed

277a6ef03aa80288f7b6782172ecb2d903a40540dd3a6f617c3d351280fbdb36 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

167383fa91e6a1fed32b3238e14b3e9d

Commitment

Batch 65,864, Merkle root 4a2dbea1567337a824feb8a230d7b568140719932589ab361ca7092d276e01fc. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 2f2aaadbd0d92800a86807a446a59de41ced84e1b4010560fc18b12bc025bac8
2. 30088849dab4aea3f5592806ac514b6ef19716837d6ef2eeeab59227ad98cdd6
3. 7d05c06abd74d6b5cc9c698b23a02356bab8f9f135f97988522805b543825a51

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.