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

cb8883aa1e44e31de53027fe7f9c40a9c498916c496ae734c61c91537871217a

Seed

1bc01b9bff572bc49102d26d8bcfb4167c5be3a1f2bd53d9413142b9f6f8b2b0 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

97d3de524102053f4127728fde8b628d

Commitment

Batch 59,994, Merkle root fbe647e921130ccf06b486eee360daf6c6170fc9d21a7d035332f82cc228dff4. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 5d27594fa95b96913f16d5dc613aa3961afc9aeff7ea935d38057f8204007ab8
2. b1af32ef6a01e97222dbe4b8a5f9d821790cb41873fed6fc44ba252fc29045d3

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.