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

317b340813a193fce9c216dea11b0165585d0af122f43987ce006777feedc3f8

Seed

9153cd4c811674aac563deb0de4a4adf4219a4a791c0b517f057d238776fe840 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

624906e4e1971376b73f74dadee589c9

Commitment

Batch 63,595, Merkle root a3e528b5ebd06bc24afc8efbfa03e7ad8c45f629f3cd6de0a762bd4f56165760. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. c7090154ee72886b861326da55b48e93817665c46c46e88a9af32226056de36b
2. 9e0803f0f17528d6b707cc5f280d4c94cbb7c3d6dc7718c5119b8128e2f1af71
3. 4a519ee5554100af191a7379ee0edee8c0447fe1b45ec1d599bcc5ce4bd38a9c

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.