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

983758b9659030e380dd6d31812eb688d58427a3f21ee4ceba1e183638ed1b8f

Seed

cf30d69970303d91427893eae882f1cc521700715cb861033a566d89400d9f61 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

132e7bab9532bf4455cd86d3cd85c009

Commitment

Batch 72,469, Merkle root 36f4cb2b7198f7b75d0e2b8c00205231458b672d9b470331084a7f90562412c5. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 8cf9c24a6e54786b90333ba1469954245459605ebe3e0be164e0de2b75299d81
2. 8c904ea4567902ca5aeae0f2b14328b77de7d06c6c4f9dfff7afba30c0cfc8a2

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.