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

59e74541c7e32e9f32b1e5a25520e3742ed40fd64d380cfd434bf5090590a7f8

Seed

c415abaf3c2822938f5606fcdc1ce65c499da5c2107e930f1ab1e6e75366a808 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

5716d8df5ec1c7bb9ebde1b55e986fe1

Commitment

Batch 57,633, Merkle root 8a92f5240f969c94b40804754765d8724544793a58de6d82a3d14512bed0d924. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. c13821dd52e01aa5f57ce308bef0bbe501f2bb05bc5e147ac5a665a867eabd95

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.