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

58910e231ba7e398cba4eb0203187f58f7160db0e47e3df9ff2b7b5b9a337e1f

Seed

ec9dd43a6c1f8ca3db2f63680f7314c2811c171ee5d6871bd78572a954d885a8 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

ed4fdba69be1cc395e5322435c97596a

Commitment

Batch 67,184, Merkle root d2936733bf4896353346efc51ed3014fa1424bc944c7f540faea73d5a06feae0. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 06a1bdcd584b1dd5e3803fd1cbedfe39ea5300fec556193253bf5a913547afa1
2. 172ccda0c66d0a0ccb4fa5f0f05576dc3beacb6c508abb89f8c65bdaa45ad4b3
3. f6577f9243a317a59332e4bc004616907fb04899477960dcc8e73fa104586f42

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.