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

cf41e5293c53b93a11565c0cc071019ed0257b3a03c1bd97de1e74f4f9f8dadf

Seed

cafd27ea3caabbe07c56e73b2db16ae6faeb413c94a63231cd7613bfc50e43cc SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

d40b5f0370292bea8e0aaf0ba2bedbdc

Commitment

Batch 72,671, Merkle root 2bb251cc29b3e7fd71509d251ea8a4a2fe3d3dba210ae5e103b182c29e35b497. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. a91261a930a55b437e5ebd280ee6e8b378e34c3327698c51f50779cdca252fcb
2. 5253b95866c18fcc8cb4904e1f469cbd383fdbbdd67f8396a6255e0e421168a1
3. 81d6603db5af6f719610f2348aa5d225113c0653cb4486e6b158907d0906f092

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.