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

43b388ecbdf15d35e202447d8228031a5e36bdc5be0e588733f4fcdf4d6dd941

Seed

97763a9504a2afdf364190c2c18ae4c013986a53b98853231385d240e967fa0c SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

79c62c23c564aefee802b963f5ce6d59

Commitment

Batch 67,534, Merkle root 0e44c6e88dc30f892a6dedcfa18c22ed22ecd967d4e4da8973b8bbaaf14a8f3a. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 54e86aa9f3c3ed406bf4966d919a498d6887d12f63a8ad9bec0345c24aa55aa7
2. a5046e534357ae5664101ed429927e753796d203e1a58810bf0b865cb447108d
3. e96aa82f4ed84ef0f3c87d59a318832498bda0bb5449f7b3ac69170d53533f00

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.