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

0ba8a54b26af2150df84eb6240ab12e2c01b9297639ddbad02f3211f4f37907d

Seed

8a04629e6db4cacc3526dcc3c421f12f89194c81d3506ad10f8d5056f1340611 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

96116b251630850466e651dcb22fa838

Commitment

Batch 55,365, Merkle root cc11bd17206c63115f7e4389a5e6bc1e94e38a0900fd4b0ad51b08672bf1b02b. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 9b11632f15dba7fc1efcdb962c80f891027f2438c65323f13beded288f2fb589
2. f84a339170e090fade9ff22b1a5836fb86af6081373e2bafec7a29625f0ac5af

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.