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

b1ee47b11fd8881aca8f58b8e466cad02e463d4f5ff16178e1f53cd7698095fa

Seed

ba6050467b001df14d3650039543c6b9fd41a5e64c611280c6a78ce85f032dcd SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

9168a711358c993fa2c6e7da87c1ea31

Commitment

Batch 48,925, Merkle root d7676ef14554c44b41c1390a922723748f6c73f1b766b71aa253b238a0893e68. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. c143c5f18562bffde1805aea5868536b200744c20ba905fcbb61897495b2ce76
2. af56655944e4e662cb6f3c5ee3915b2afb5f0cb806e81e514db47a3590553a8d
3. e6d40b7970a4dd0579345a5d6464fd163a374b5787030c22a2887c9f3d9b6306

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.