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

cb01dbf425b76ea8800f2fdf8cd60994c1501e64b06c95cb24749bbff46df5e5

Seed

511e3cde09f98b2e4eba5074321bab29b26370ae242f55118e0c196471066f84 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

8a71bcfba6354d54cd14c2d03627c6e5

Commitment

Batch 62,212, Merkle root d04bd8a15b4b71b5bd2d97995bf5edea06bae52dba2b6e59972b3f02f85d8265. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 4065414d95dc42a43afd4f28ea319fe265befe350d8f21f020756d4bae6f11b7
2. 64d591d388a8dbbc5f14e090e8dffe77e16c0b67d0c4af211c57f7baef297aab

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.