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

cdbc48b661a4653204c8be2f83db3fe9076e83ce14cd9d20119a5641649837b6

Seed

89452bb89a347c981c8daef8b3e7db2030fb06b4c811d3c7769453074fcd856f SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

972c7994ba7ef0e8150872ec8792deb4

Commitment

Batch 59,687, Merkle root 8e84d00e2a066e8a188c867bbeabe99fb3d248bcdebb455873355699108719ac. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 19cb0d248be4bf4bc083bfbc7d2b754cba6b14450119e7235f1126ed8e589e72
2. b23180779336f16107c0b5c1cb275ec47d28690cc2731ba0f91f8edf05355454

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.