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

5ba23bc0ca03cbf6e5fe5eb473c5b052cdfb5ad81483635202c86748e3d41034

Seed

1a0adf9a623d81c1059fd94597f45f3bc927562ffae51543174f01e6e3fb3dc6 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

57f83acb5fb0ba34f1e500153c3699c9

Commitment

Batch 52,910, Merkle root 1c26a4b2d1ac2818812268691da11bad910cad9d3fd9ad5b3f35ecacd6cfce2b. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 68b81b24c83fd31e45c0d5bae4ea5e760f97a3092d70b855cb90b5d25975c457
2. ea50bad5f0b732d5ed3e4c86baf5272bb269c2540aa75c3e8b08693e5da853b3
3. f539cdf3e9768f68bf7d22d101cf96d0e88d18f08d26cd5c9e584c71ae250714

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.