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

0d91ec64144aa01ff97d10192c4737c391d6d9fe734b2c9300e935522506e72d

Seed

2a89e86c01da0e55c275c2fab89fc936ee1bd5bcf6c6b912b8d697ea44e01881 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

582468f9c9666e4d94726e9dcab1b8d7

Commitment

Batch 60,321, Merkle root 9c029f96a32c22aef38eb2bc115c1bcb85a34075d60944ce02478a712ede35d0. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 5294881b0fb370447455c5e1c03959a0e4d1c9a1488768060a43f1b13ef6672e
2. df4ee1ce7f0f4a6e82c685767f7492671b8f392d38003a66489e283f11378e9b

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.