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

fdb97bd9d6c220847df0a08e8ba702608f3a2dd66215dab444f35a5d2dba3156

Seed

5230789c3d53b2c7a22698810bc5a97cfb24467547f573b0c2c47959ca585e5c SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

de80784d29ea9fc975b748844a7a2acc

Commitment

Batch 65,024, Merkle root 89be937b15132d0f46b50a23d14940d3a4a689810a6a24f48fca6eb7444b3c40. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. f61e33d79bf23886a1983c08374958b4d4dc08bf44d35e1104fd3330a775c16e
2. 8bc765787e1fe5b040dee461e4424218e350ec1f428cee2a65b686f284c7a311

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.