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

de29f5fdb3f8d9489610d211b8e603fc6d7d8557c7179bcfe8bb183eed854361

Seed

f91b208beb7b05813ae62e0988f4cfaa1e605a9fdceed69008299cf75ca8c151 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

8ce4a95c6021a613e3bb84ea831ce554

Commitment

Batch 56,685, Merkle root 2163c651dcbcfbcd733d068ec9f36cf21a8c75e6b006ee73d7195d100bbba66d. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. fe2429a2bb2585a73af3b7cee2a22ce3012442bdb051b3a13a0843e29f952842
2. 8308394aa3701d31c8e95c0cfd69b80e5c742ae74d36c651a0159d9268641882

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.