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

628763e29d107b26129812cd6c944e3d99e5ef6a1b77e61c0be4d8d6acaca95a

Seed

43fb26a16f9e692394b9ca6d43235e93302db0eb9854ff531a6a2c7616d01c24 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

e093132c13ff4c8d256e09a16ddfeade

Commitment

Batch 71,654, Merkle root d4ad78847b8e6cadf34d2aa517a3fc55d65356296a3b4ca89fe2a3f0fb2c5b50. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 6ba537864b958d28471641338c5cf0dfa0f54162407349be9efd615eff4faee3
2. 46d0c3c59b7377f7261abdf59434f11e75dbef1db54b9f76a6b4487e368d6e33
3. e226f8a4a357cf823aa2b61323f6af9af71eb8d370472fda0e821317d12001a9

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.