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

b80ae398c74d8aebe6e12095e3ccc6534132d2b5713b980936a6a9a7f90e861f

Seed

63027bf889372ade826f94beb40fa3dde774ccbbc17e2377d92c099537b9cdfe SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

ed1d168da5f9019cba848362da098d58

Commitment

Batch 55,532, Merkle root 7b25461c56db93e0d21857224d35f8abe895fefc358c618475c55e74da168f1e. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. de7c9ecdd53b474c4c8b478ba0b7eb561e497a1109778fd8c962d265ac33b78a
2. 9ae1fff63419414a0f59fcdb0d5b48568452eecdb1c029f3704d1d3a9ce8e390
3. 2f338ed8ffa614c865318f8e249057d8ef31ba5234b81345fd6eb7300f23396f

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.