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

1d0ac4cee536b77df3eaf7d24e2b1b667067c78cd20e11a78562c93c0172354b

Seed

94ac7bc17f373ead989ede7021f0fbe78cf37a98cea86269ba51d5d092d72c40 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

2b4d5c5571c37d5df5414c3beafce1a9

Commitment

Batch 58,415, Merkle root c694f107b120c8ea10d4901ac417758c4895d059de5c302faed4c9840fcc7cbe. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 045e92f49cec39e555b76ecb89b31518c7ee084481098ed1be0c544d4b0020da
2. 45875046a3c73b5997e42ecb5c56c36317ffbf32cdba7881df6a0fab1502e919
3. 4398f16221b23262152827fd510fa822be0abd66bff1015687d2d25c5cb6b2b5

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.