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

d91ae315c6482a0725f3898c0da77b8e624e4699b8d02885948c49e8caf79c54

Seed

9c2b8869f720d1a06da0c4c939328686e242fd70083f5d30f36276f8a19d1bd8 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

9d6a2547051e1b0df343a7f816ee03e4

Commitment

Batch 56,803, Merkle root c5c6ce1dc1cb27473b047af60b8ab82803e2dd0c0e79d8fe9d5880b74ac23593. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 5604304e62a6e4b457e61826e9e28357e01fea5304b65c21e265eba1249d7f1f
2. ec71117ff80db36e30e1d06afb2225180c9f4440168e8e7eb7d9b8e5be6af8cb
3. 963ad2291dae6a954009368c0b0816e80ed18e0653d3ae6bb35f233806f85676

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.