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

e2e7c15430eb46ff96dfca45733ea205980bd753c65befa3c78eb37d91248af4

Seed

bb4f3aebed02bd011c86d3737f8fae3716ebf5a15734ef86f8105d5505ea4074 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

9afab8d8dc7d7044333a168c91f4df94

Commitment

Batch 73,390, Merkle root b6979bc4760e5242b4bcf6eae36f50cf574d7d9b937ccbff40dff078c211e89d. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 0df804a4398efca56ba42f4c75f559fcacd2b91d67494bc8b746f45e26951bf2

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.