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

c4e3f7393f66243479d500aaa0f3a3c109252002aa90e4248a4998ef2a07310b

Seed

9db5576863b6c9379f7a88b45f96994333c0b2d18b35d02c30e2d273841bb4fa SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

c8fc2f9353c258e14a32d8e94e69b072

Commitment

Batch 48,808, Merkle root 3f3dbb895a30f029136519ec8c3557e24e2a788898e6262fc6abfd7b78b3e983. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 46d11d34d39bdf8e46c33987e0cd8248ee95666f6bd4213dc7697c282a82a3d6
2. f92424d19bd032f65ba71c2d510b3c48bd72e6c8082e1d486f993e1b88aecb95

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.