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

4dabbeba8031bd62856138ec41642a658225839467f43345f821d148f3b56939

Seed

ab84246201070b1c1ea8303d77dfda4c5e99d9703ed4df1399d522dff3c0a7e2 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

2bbc55ee389a2f3ebfb0e0adbe8640c7

Commitment

Batch 49,490, Merkle root 69f402306b763646e7e3425e88505233fdb92bfa1c2ea24d67cf8234beba1e8b. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 83acdf75f0c7eb33d309e5b1c247d4d352593d5eddd63db129491aa8db96ea3f

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.