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

a7d1bfb38c053722380a6799fdc4a20344b06793382582a6ffa259d4e336d743

Seed

e97886966130152cac0c044fcd498ebc861acdf1081cff556f4fc24ed058fd35 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

bee63b8d1be190c6e175864e50b9c819

Commitment

Batch 62,526, Merkle root f131bda7bb51e0fd31852350248b8e477a65d43123c1652a9184037bf52ea8f1. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 5c0f60dc5e059743934575e7a4a98b7f2bd95c1055e2ebef4f1a29192e190cf3
2. 1d6a0ddd3f3d66f72c4e167fdf13bd0f67751c4360d311198f6e489a54c1c0fd
3. 89b900c206bacff89645de9988a0804749d1ccddd38fa311e575bb1828637a19

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.