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

67139da75718a28a287df6cd84643e1515554129c5f546f017e41f4d338ab447

Seed

af357c404312adeccf8d63b2ff818206007beebf5325eb59786dd01d18943ec8 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

b50734d0282a2137897803929f50d5ac

Commitment

Batch 47,577, Merkle root 1ce09248ff1ae3adbc07bdf5e1fe77df24ac126c83c20d382510097a10248635. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 7b97cdae53008b51a24b814552e9be6feb2b26e7c0b1f49e7a83cd94d811c0e8

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.