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

85f27707f5b6275f98ccd7ac75d02cc7e45ee7b785db47f929e10eac9716b127

Seed

60cf20fccca043c05f6a3b40c19203c6615d529fc4a79f31b901d80e14c9f150 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

1caafd07a2962d557427c15fb6aca59b

Commitment

Batch 67,452, Merkle root ef9efcedc34d3e62e9fc690e593a9dc63086b8c12bc2a74768bda55f670e3a4a. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. a2d212b7575cb8e5f584e21cc40dbbc99ffb5c4f81fdf9c2e19b0016b030c42a
2. 570012e5f01c282e1535f29b6be44a25320f0580c30284f7bece81c2f5f7facd

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.