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

88b0bdb0fec6b3f5bd4e3e049a24922d714689787d5c04458526ba3477d66ea5

Seed

83375277973758d462cff5bff63a2eb5cc1cbb112aa758d2fd0a331b1afdcbfd SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

f15680e1ecb9d0ac97977670ee207f37

Commitment

Batch 62,791, Merkle root 29e31159175013e97f1f9fadd6230c903eb4ce70db89de425cf9119ea7a58062. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 3046008d81c0e804583baec48709b34985259601dd5b4c1af6baa69997c04478
2. 86199ca326b996000707c7ac913585a84da8d51d6f650c98e2190ddacd6988e8

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.