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

5316281928f7da9abdd3e47f68ecc38035e8ec44086b163a8b00ff079466b404

Seed

cc334ff7e7cccc33ed6ea24a4216826ef10cb491dfaa1e564dd5b91092d376b5 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

1cedb6be5eff0124984cab39585c349e

Commitment

Batch 65,631, Merkle root 0db5eae2356008cf55c6d4486b5d0ec6a46d889fdc204aebb84ec275d780f223. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. e858fa5c938a70ce79dbaa348b2336f74717918c864333deea6af57f34980c82
2. d76f473f30de02b4ffa45cc0f7e5c657d90f5dee5337b507b69104f821c536e5

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.