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

9be9b489bbd2dce088169b15d4844fa8bf5887638ad0f66e974f5076bf1c77b8

Seed

714c79c674d6d9c89639c7f2f1968551f4fd06d5d374165635b4f4d37d61001c SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

fc9dd69886fed6b918fca634666b93e2

Commitment

Batch 54,555, Merkle root 351dee4203afbf4ca1c1d9bea89e77cafef3c190a860f2eece3ee4be9a4b347b. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 93184185535c2fc90bb46b38cdd6f73436de92d274c082b3611e4dd8efe4c0da

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.