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

0cd1ceda4f7a81bdb657b24243430126e2c38c9d7b7b0f9debc635941695931e

Seed

2583c25e0973b7229e26a9cfaa55e373c2295ba6cc33ff4f9b63a804b47247ab SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

2a3b99c8e2f5b6187350757a6540e57b

Commitment

Batch 66,336, Merkle root 0d511c4e93be6fb8980be80ee8b7a6e84ed8434ffa1f7285070598baa2692f40. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. ee7727932758c02800ac0d59015c38b7ffedfb659ce0a9fdc9bbb782504fa8ba
2. ad27ef1f7adbb0b10a80de501750f355e9eeac0acafca2b798250b91a597fc93

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.