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

9074823a97b54b74a4775ec22e315aaa2cdd8cdcac3ad0e10fa1b30e4539fc5f

Seed

b9070aa8001ef50199e54c29f5a95f81a3acf2afbbca3e6ebadec5f54ed02e00 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

451cf3866a45ff7a300f98460a88b2f6

Commitment

Batch 67,910, Merkle root a877ce333df4040d91da2b68bdf3df4d877f99e62f860979b0cd1a54236a2053. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 0bbe8f90d1874d4a7a8c5d78fdd7924d8647c40c3c15b9094a9168f86d572969
2. b9fabc2320a394bd4f97f10ac11bb8de9d7b1cc0c44f0fac8173b10678f78ded

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.