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

308b5fbd912e804b2b9ca29eab5ae94a6d9b1c41fc9adb9e59822b29cbd3219f

Seed

4ce0dad87af94b0b22c634ae083e6984039a6d08d15912027d9dd3ce7d5d4e6f SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

36122b6c63302b2eaf2ad4febdf9ee31

Commitment

Batch 65,967, Merkle root 053b25b478b2942321249e7e04f6f0bea641c742c631e34b9285ab300f45e671. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. c432638682bded6a26821230e280877ecdf718dbbbc2bf2c1989fd3cafd6f2b4
2. 770544f7eb024502a2eca2f14b625fe2b00c46b9be0179866e7b7b0ecfc7a794
3. d97149b3c03263395a9531289599ae22110ddf6fd66f4cdbcc3d0081b2b9a648

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.