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

c97cc9050e155966f6028499cffc5fde2bf5f010f1e46a9c7cda7ffa6dbae0d2

Seed

177eaa01af5a9d9eb288f69ef57f8ed8c9de98ac145e0519e701e74c59b6ce44 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

73eeacbee7568668366ff028a62ba2db

Commitment

Batch 71,208, Merkle root 9da29f91e1415ee267847bdef0887f198c3284d55ad1d0baff31bdf88958e514. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 1a122d5cf784bf6950f71aff1c41a1acd5e41bf5ede7f2295703642917a163c5
2. 4ed842cf36b129556aa63ede11dd6e6452e0e19e4d7d27b1b2d93ad587405395

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.