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

5a9ead8db3cfa7ba75ae8c2fc721152b80fca8915430c611b33c19896eec7df2

Seed

eae67ad4ae25ac245275349529f667b7031f888bebca304a138b6a24be26a6ff SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

0e31ebeb954706f08d81a451ec9743c4

Commitment

Batch 48,165, Merkle root 32bc1362462595f93516ba79c64ce8a647a6f463c757327571bdfc731daeced2. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. d60662b6547179e2bff189dd06a24c2f37da05e14dd5bd4efd6628f24bbd70d7
2. e0164d5e04024b618f06acd0d6c8e1f46a3f673db8ba2314b5dd9337c8fe1f00

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.