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

282c46a31b98a273ccccdd8e187ce5860dbd662614efc75b8e7f3ff5bef2d36d

Seed

aee29b405dff05bf1c54a5fe26108c104ad4020142c0dcfc4c4b1165602e4b94 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

f1b1bb6c7248a35e5bdf9cd8b11b1661

Commitment

Batch 57,148, Merkle root 7399d445c2b9c0d955e344f615df38825944d3a89ffc3ca943d7834ce2392a6b. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 19985b51302eb890388dfef29c8d1158d67f382bfc2637d44ed46781659de6fd
2. cb0f7b4d200c608da14b228f4e6adc30b4d706c24334b5a7e02c7b46ec69274c
3. ddba702e2ef202c02806bc5213431f8caa354068e3e04ee279ccd41ca2d5be14

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.