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

9ed16018ee161ef9533a0493469ec050ca7b7d1e62d36ceacabf206fbe961f42

Seed

435e3d00afa43250e362685fc4a324e0db14ccc8946371b4ef6512b50979c355 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

46ecb3237965f4ed628a9443f9e20e15

Commitment

Batch 56,352, Merkle root f3c1853a16eccdadef6baa971de0f2fd47c3a14127e43f3fa5767e55bec8e502. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. c8eed2a56a79902937d1264fc31e00e8d803ab873f803ced8bd01d7dc4758b5f
2. bd308d1fb7aefa1fb794b98ac282103442e03f9975f6348ef8dda74380e2a89d

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.