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

30dc2cd1948d885b530a5f957ddf9f321881a41c7b2d3115f8d8ca4c1d2aef3e

Seed

fdf243c48f448290a95048524101b52519a9aadd444de3d94c5b74dd567f423b SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

4cb612e3a838c8c5dd3d5c02b9ef6e35

Commitment

Batch 60,919, Merkle root 1c241321cbdc060df408451f0183e8ed2ac9638b2d320dc600a90ceff07fef7c. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 1ce525f26e43e4479ba3b7d036f46b6c0088feb91f552ddeca40490b545fc5a9
2. f62faf49f958da3d541c2509c01640a3b9f27a9e6d0f90d24dd2c4121141399a

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.