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

14d1ea107321ba228662c34f568fd64f4dc7ef2f2797420d394e7b5b5e1d4627

Seed

649b1462a90f8f2b702573af86ca04a28cd0a947308bc45ef2ce0a1ae73b8851 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

459a94686ad9feb4386fd2cd7ed6ccf5

Commitment

Batch 62,650, Merkle root 6c3d7015e0f5b3dbffdf18c8c1ee868ed14c92d1c9f4d10846375c690f0f1e30. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 8e0300b820e9fc2c0454f8e6835e0e493a02f2a9d9ec51a2d375b4e1fc4dfe7a
2. 8da2ec49b8aefe60c579ec4f5988647e6666771cf221ee67d795aea86ed012b3
3. 58bf57139513f2e650972a201afe1a8bfa01afeb404c413343cc9d1dc3d0351f

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.