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

141932fd926119fc95287c30828e14ca490b719aaf350689f4a626d01944af44

Seed

9311717f7d4d38afd5122d8869005d59c9ee175b40b5bb9f30ea80ca901cb001 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

fdb3a4abafa6fce87c64bcadda788a31

Commitment

Batch 55,083, Merkle root f9e4c3c7b7b9f18ff7014f42d8d8c63fb76b4f4654241af91994a380475c9ff0. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. e4793fed55cf86ece7094d244786b809002cec8ff3b77683484624f0073bcf65
2. bd8111fa0059c3cb8a8a91818db7b8980be10246c8c8b557fa5d11fbca6e9ddf

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.