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

64c9c8b5c99895ed49439474c272eab94f8c06ce75abcf5dfb5f2c41eadc3ff5

Seed

1e8aeb1cad14b0a53e18942fa8ac43b96096b5ae82d4dfa660b3e6cb492c9ee3 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

ac5bbd74726ba7371600e10e2d24a7d3

Commitment

Batch 60,736, Merkle root af451d1d8984d6257687fb9e2315c2ce0ca1b7170f3917fee56294519aede47c. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 42fecc32372707c8f8d43d77626b3a56102ee43c7d09be7cfa345c41678a5668

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.