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

c261224143903cf085ef9319111eea9b112bed2fc04da46f201147873defd4cf

Seed

064ee23e6d9ecbd289ec55ab5d04124ed62397de2d7bbeafb53325a0947b5761 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

eb191393d5568d167232ca6fba57a7be

Commitment

Batch 70,918, Merkle root 0a821686221ffb20b56f3e18f2c3a2b7539183fa873a8682a04aa4a66f8c109e. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 474780b64eb2404fd1a6be0772e6a96c7bdb3cb702b3ace74863d1b3db137d37
2. 340b842c1574a917c637db153a8f1f4c6d4520fff2c6d22e0ed0090d970354ee

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.