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

83f54390585c8612424af94b5d27d5b440985944d03ef409403f23cbea755a02

Seed

ab7f0ae49bc4171ff8a3d711bf1e74eb42e2f43af2f4ef451398ca2b516355dc SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

5b417bfea8844f0ea672bfa6e12116aa

Commitment

Batch 65,661, Merkle root 83dc8e430e8cb769e9833581a15ad9a45420af1392f2b9b61eba9d4c05bc4dff. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. f6f08230e3d59af98a59c404339f73d9b4fd480524c16385b7a2f941acdc83f1
2. 3a33bb0827e46b9208650acf444962d5b97c4737b7bd92728b45b349aa85d6fe

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.