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

670b881cda94e1355261c4c986f5c3bbe9fc28fcdd08293f37e489fe76703ae8

Seed

c9ed0df19436218f8ab7e1f4fda5208b4437482d846a089c3ba7a084ab405cc3 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

b4cf6cf8dd260de8b4fd851feec36ba6

Commitment

Batch 47,180, Merkle root b35da862dcb571caf8be30bd3e4ef069716bf14dd9667bd22ecdd0a430637436. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 82ab2b4e0115f22f0704f539d17efd5fa211aadcbb40d3ffe77519a45a3aab0c
2. cdf1ab3d50e950d353bbf1365fae983351cb95abc6386d0905dca8161570a67b

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.