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

3d236f2a110de89fcead36f14bb052948d1de581cf4d2ab36d1828961f27e4fa

Seed

10054945ef3990824413ed3796b6dd80cae327af3e9ab0a59d2e1d74bc3e63e7 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

16c0e7ddbe798a3c56a075aae9486354

Commitment

Batch 72,924, Merkle root 230d40cdc5045511f5c802fff9493e7d77ae6c837c3d8851a04c0a9b71dfd451. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. fcc941683e2cd2da3a93593253881190d2edc2545d2196f842c69c7f79ae9837
2. e0de75a2d5ab4bc9c51bf90ade2d547168fa46fa2a5658169d26d8d1d478bbfb
3. de3dfcec493086c749ca0ae1e91e267ece1364b2efd58c8e42712da746a38b75

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.