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

0c79de9c36fc5548723ac7fed693269c1f6dbc5507d7f6ddec69d83a562db455

Seed

27960cb381beaa812dd14b6ded4aec7f1971790c16c58f0295d20b70a508e930 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

a2ae54d08661357d48ba45cb2fc3ea87

Commitment

Batch 59,222, Merkle root 0a8118d79abd9c185a2f21851fe4e99a019a99d99909ecfc55dce15eb5111e4c. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 6adffa0adc06fe3127b1928225b5f5d1717b8d7bda8a8e4fd317c9c370e68e63
2. 8c11b66d31a6a3cc1695b0c97aa37e35b4516fc9225b61c49acc943fc12f6885
3. 226fa61e47d9a2b5d77bc1eb6801066ffb545250290deb9dead82cdb3e4e1a5c

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.