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

ef8b2d435e078340dd0f00e26236c788deb4c93441ff0a7213412f8c5fe03a06

Seed

11edc51b3dd0c45f79241de1a3e95b9c7addf7b09a4f21fcc6a3d22ced78dff1 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

a3281347656fb7c4b0304917f37eec75

Commitment

Batch 60,179, Merkle root cb9fc682d449727582be1c8960924e9ae38a1bc4946d57ff13e6e5a73c7dfd72. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 7fe9324758f227a1b9af82c156a4452e26e033cb6b30ae5b1420ac2f256dd4a6
2. 08355247179c93e5c544c7a66d524642598a6f0211239b1cbf8c0a75529f4e5b

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.