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

eccef9ed6f67834c71fc60327dd36f515cf3f4bf84159ae7f4dcc844a68387d1

Seed

2f61400fc81af8ad87d27818e38434116fd606ff726c864f7612fce337edf4c4 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

9f0ab31bcc925bc1fe8241d2e81268eb

Commitment

Batch 63,400, Merkle root 6e06b3601f15b9a4b7b2b5cedfde7c854dc3084047e0f8eb0cf5f3119d8fe4b4. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 073af101762a4d8b5a14e23cb1e9addc23c0a69aef4aa4897d445920c113bb3e
2. a2f3699909bb1b237022b6d0eb7826bfa34f3bf53b86400117c3d95523fdecd0

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.