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

23c824e24263c097d99a197c6f5b608fc1ee7f70219a5102b6a941f6728cefcf

Seed

720b88d7ebfbe3556c545d740cf6b92421debed1d5225a7cd298d3ef05d0d0f1 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

dfeee4fde7c72bf6aa0b6ec4a0a246fb

Commitment

Batch 51,659, Merkle root a8a446fb27b76a0fa67248f6c32530bed79a4a09fc2e854f7c42ab6d6adbe358. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 49b58c4867509ead80130ea14fee49768ea382aad4a09819db8a8bb95b997876
2. afea268b63e65810441186b1c8838145f9e2c995e0b30860356322fa29c98509
3. bf9f4fbc714c550052680328694480d409d8f3517e22f58ca2908efbc868b71b

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.