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

ae98fea3d813d90947322f3d9706b5820e6b97a0ee74eb6043b30f0a139f5af5

Seed

56ffaf99800834a6879aa3f37642c60aba3cec47ce7f8ad07296ff331d0c8acc SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

8c69f36b242ae52bb269856d4c6b98eb

Commitment

Batch 49,223, Merkle root a9410a01535ebb52227c0d0141532a6c8dbdcd849ce5ae623193afa64e5dacbf. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 17f48d27ef0a4afd664e597e762ab9db2909915148d2d21cba95a0956472ef5f
2. 36ea75b67d407c013cf7df12d989f43554113dee41e627624e978303083c1898
3. eb109534a2f8805eebccd14f41c351976f5c40fb2f99f0b10441ceeb03c59047

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.