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

f2b46b4543c08ec8e91fc2020a0b8fa3f19e49172c7f7c0d039bf3a66562e620

Seed

7707a17f2a0d4002225a1b860a6018b4b7a82273ec2ec2d8077826b3317b505c SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

ce0742f9f86598397194a3718ad3e231

Commitment

Batch 64,722, Merkle root bf321917eae6cae52af66c2c3f1ece1a942bdd1e9ee579d3f401ecd98aa894af. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. e157c52cc54458a1f70463bbf285a2ba39fe933f185346962fd78a60254b7363
2. 8f8e7bd0dd43b19787b039e61b9789bc6dd6b33aa4d313e7eb2e764834492784

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.