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

de21df7eb2edf3755af5eac4536832e339bb4a0e667fd846c79e3d0fc900e047

Seed

3fbb2b7361b4151cb0108e31b12b0b4859f9772c9040634605e46bcee31a2ff4 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

3d3dbb42b4bbb5f50ef6a70e0be96649

Commitment

Batch 63,647, Merkle root 66d1f0b16bd9e6311f9cdac2495f987da150010795bfd62780d559974f727b32. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. bc53a1a920b84b97f9f5936aed21c85ef6518bef2024dd16595ffc97950b3d60
2. 77807c18121e6b83ac823644272761807503ed53e41b8777c1ad21d9c6a81444
3. f3c51e18c6f382803f0642e9df9dddeee624333f0e6496010bccae1f12ed2b75

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.