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

34f9e5d1095ab9171c67f0af08635014197a4c30a41059d444133f2021f15dcb

Seed

101ca63269ddfeda8761cc4a9633b593fe5851fe90d1f1e24f1f643ca27f80d0 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

6c6d36f71e552ad5d8c9dea0e74c78e5

Commitment

Batch 63,364, Merkle root d1f705cf5dd209186bb8c6776ec02eb73291bae4b0aead20fea5a791589bc779. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 31098fc97b4f9b6e919992247895f4ce589fc7f4f4e7194f7dbdc3edb5ff9858
2. 78792d527c45d56314b32e61a859f0baf2c5f58ae18f1e57bc1a3ca761e491f9
3. 33aa0e7d09da565cb5e60bd9c2a04824076b0046035c7c801f9bbef66cbf5886

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.