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

f0b87a299c474ba183fb4f858053d16b5c5df030feca68280201e21c14e4a1f4

Seed

84aed2b820695451e7c9e2d0cdaf28fc83492ed06273ecee6c5fa8f5891ace57 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

ebc0f949ffaa54a8faebccfeb7cc7cae

Commitment

Batch 60,366, Merkle root 8d0ab1b8b36ded07fe3118d611715794623ef0e7dabd96233a3be3a4bbf77f3a. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. c89e28351254409fd68e11c417fd409c6fbc1120d871f23b877da46d68ffb8b0
2. 54467e056323afca6212136af170ea9c8d85173f4e9b5f107e7ec50eae8ba07a

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.