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

9b8b7f8f491456714a2a8101d2ca9b8c7201e1f052029c2fe9b39fea21e85a74

Seed

ac68a1591673b2adf7abcad42fb69a3e5555b7001b8f4d474d43e082d51246d6 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

8cbd1d00005181391ec4bf0b35488483

Commitment

Batch 47,500, Merkle root cadfbe3928f31c711fd23739579095dddffc82bf5814e0c5b86b0aaca7b7a286. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 67d15d0b4907a72271a8a9f83add25858bed31a3964b6d97f99eff5b5769ea81

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.