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

10dfba76d7b1f5df3eb41869e2eee73fe53eb9e4caa8be4f4031963c57518e71

Seed

1f740eb95dc253201716631183be10dd89b88c3fbf8d6623cbaf8f9634c0baa1 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

cf5702ea5afa05c39f4fc1a28155afa1

Commitment

Batch 55,627, Merkle root d09ebb0156a5838b573a5ac3ef7b0f1f1682e571e89b07d55bab0eff159bf9bb. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. d39b589e0bf336f9e5c44e1073f5d7c71d10befb52123e28a92a06490c655075
2. 024ac63f1394a25ac0a2a6cbea96a7f0788b38ebcbcbfd852ce6bfc3d6a29c23

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.