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

415883040dd492132ef6ff01351169014667fe7cfefb0d1cbd558ec8bdf7f55d

Seed

31f7ed44803644482d1819d84ee1258e8fb2b77dfc54ed9e4d2b9cd2f6d17761 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

2d8e5b2f8836f92bb82497d0bafd91c5

Commitment

Batch 65,145, Merkle root 2cd392e3779ea1c9397482b3f81f16af3a3786e1ed2ce2ce9e5d9f0164a4ea79. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 3e72625ce99696435d05709ce35453ae4ccc33fc91a99490952ead8fc58a7b57

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.