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

a989a5133d906bfab0ca3dd2eb370c427f9e0fcc77b603697577e29aee30206c

Seed

5d2cea0473eaced17e185516fbf13be0fc249602b5b599da3617d9c94326a102 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

b61299b3bb213957550b763f62228bcc

Commitment

Batch 65,422, Merkle root 92857bce88b0ed385e8b142b34e3b2014123ab184f638a0e84651a021bd5e16e. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. f525d36d72c62e28bc3643e3a08972501d9cc67700267b7d693d50eac2e10258
2. 1429c1a4d942cdf288a709213aabd9eece79af610441c865c353a9648f24f217
3. 33daba18efb24351e39a4a4598e7014ce739da707048afadebb1d8448a45915b

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.