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

083351670e73b6dd77c60a47a717092c67f06d6610ae3705fc00cbf6bb16925a

Seed

bffc0c1bb6150cd069b5c7965013be978d5218db6493d8335975fab028802293 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

2b1e989f431500fa06f23ef60be59b2a

Commitment

Batch 47,270, Merkle root 6f208a020096855c915bd4e068121f86b5042a861776af31b8c3fa76864e2aad. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 394e0c2c328239d545aef4a32a6284372f4f01cbb80f956af1f621a2ef68ebc2
2. 9e1aa3095cd0c439433d408ca7d35d2dc9b30c25c75c9fa49f2b915661d1d385

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.