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

a7e1756f6328a83f79052c9e0fc02be8ef4870ff05b2b27a44b8119c17369e48

Seed

29705923951e808373cd884b9f50f8b00e493842300a7524746d997f2f90e52b SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

4f545c047416ec9e985547617f9225bc

Commitment

Batch 62,813, Merkle root 531bea76cbd1f68b391437d6bdc1eea67996daca3e4c7771fb9936c8d40ffd66. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. a69ce051aca301b94f591b4897883383a04cf354808fd701ce4b0d9335424595

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.