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

dcbb88577917d1b22ded8a85a1cb284650f25ca478b2ea57da2d9262a518d2f1

Seed

29e7cc49f317d88b95b26d161d3cae637daf95747c3192165b3160790ec98b02 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

f091874baf11392f5b8ff0946772726c

Commitment

Batch 50,701, Merkle root 62065cadeb1b2842a6a8cdecba6b80ddd13ef9ea55367b029c7bd676afd08bbf. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. f0bfe4790133af9a81e282ecaa5a488d058bcbece7d02421d7ecb9547e47fccc
2. 13afbda0fe1211dfc9ed087d9f4e89479f107c6ac795c9d361a304d5a9d1b2b0

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.