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

6c61d2d6099ce3e8033c542651447a199424db4fd950d518c7c0b1d356998606

Seed

cf94bd7505c0a32c90a753f574f6314034a294a0a0aa537bc8cf6fe8fcc846c5 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

de53b18eb3c700462b67aa346c65e88d

Commitment

Batch 66,794, Merkle root 9a5da41971730e90f4e8b131385f22ab1feafa1989f81e8ca8e077f9afa3572f. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 80470e8bd6bbd4614cd840675bace6e1ea57c8285ff320441434589e6a634c53
2. f341b2f3c8d310a12c78c7342a5fb84b244138da68c940ab8931477dabbb6659
3. d599c7dae61750e272cc26ee298f1fede3d1d32e9fa9dd80dc6bd8ae5a064bdc

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.