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

2d73290100899138ed8573c301ea633f836096bd178fa043ef4bbd6d6a9a5230

Seed

bce41c30351c89f6528b1284f5360092320cd8d4f6a02f2c8d983d8e0c819fb9 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

e85b9c57c073de618727f767d25d9d7b

Commitment

Batch 48,568, Merkle root 86cc669eaa9955d8cb0a1f38bafb5fc766fd20e6ac531bb5365d103c7f2dba3e. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 34ad08a5bb9e15ba25df0e89a469e07e3a0acc8674403c521c519da7ef511182
2. 373fac3a43d201021b0e0d7f8b821b381de048396921bcdbad699e97bf4f4124
3. 89e768d0262e5b0d68e36f851a1452ce41a0dfc3d06396c3b699169146b3ab67

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.