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

065c681229cea08fea713cc5350804fe66b868fb6de7555acc79f27e7e7cc1fd

Seed

78ad05132463074737bbdde05606a2ed44b037b70c17dac2c3fd5623809eb50e SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

48c21471350c28a3dafd97c3174d60bf

Commitment

Batch 49,771, Merkle root 785755121c0608da2db8fe4ab4c98d6b781f3ab286e2b7c79c869291be600437. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 942b0144f691296cb456ef32f562399d0cb5d6bb3834652046e2c9fdebdad769
2. 43056be413367cfa08147bb0259e0c36cbab8aba8cac1960b3be4c9d2c7826ea

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.