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

824df6596d362f6692640a84d95ac94ac64e878e496ad800742ec0b22c20c138

Seed

e996311506d7bbff7874174a3a3abc26e35b8a16d0ff5940f1f606f9cf49c414 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

6f898a3fc4d340ff60ed08ff402c7474

Commitment

Batch 72,747, Merkle root 75654cfd3b054ce009c3d2a24707162e83c2a597473602286e980ae7a9b07fc3. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 083f8f63af5fd730a528e9e49bbd43d94e73cdbe9c2a6a69882e23d72ee22975
2. 37c70e750e694d68845eeb57629437a59d588b01780e8b363c1a7d17eff4a0eb

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.