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

c5e87d8c8bd28f358188499587d727d236722cc0080b261cfccaa2c7d2022912

Seed

054b24355a8630933809d460a0b4751bb76ed297026ab10454884be62f4210f6 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

7b1bd1491f0c3493a86a610f7745ba49

Commitment

Batch 64,380, Merkle root f3746c71dca9108b18940b32101240a98ff811d363f7e40c6c103dda016eb195. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 111684dbc28198b242c9a8f304cfc2028676bcbdd480451481f0473840dd574e
2. a7c2f50f96101984cdb3cde5da3144026e9299c64dc25a6ad7e1676018e56e21
3. 97f867068524f961dc4161e486ba21dc17f6189fbb1bc99be8f7b03b1a682645

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.