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

e21182c3b29f4da4afed89903a1b8aca8721aa45e17447c2889183a59e619e95

Seed

bddc05168ecc95bbc1a675bbeae8d0f1bab7adcb0ae388832704ca4c011fbc8a SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

0bede011ab079249e624d26c8bc76a82

Commitment

Batch 69,285, Merkle root bb8f454c6a811d3ebab90badfb79585de86e2d0395c6b771510336e3ddb6413d. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 8f08d8cf7fd01b9cbce3eb92f9c934c93eda87702397ef40321ed14f54613834
2. e12cb7c680ffa9692d8ec1b93427f06e2cea1452d9b7222ff61f2daeb4e541d2
3. 6eadaaff4dbfa91602c825605f8c2dbbdf817f797df946b96a557956f4ef68ef

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.