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

24bda2def89a7d231b8cffb62b25d1ee61b9f5c8ceb313c343864f08259b6a7f

Seed

ec1ffc8338eee95a3b97fb3d408d6b8fe158bdc155cd72a2383430f7c7524667 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

2b0f2222bff1a841c35d7389d6546c8d

Commitment

Batch 59,882, Merkle root 268e33f5a274b2486a416269a50be7a0b39c9f6cbcfea8422ce061e09c8acbc7. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 76eef40f5b8130c151fd583889e2af0b7e4bfa964a95668ac71a69f76e9727ee
2. 709a0bfd8bef5239abaebfa738fdbc414b63bb9ab6f38f6f08011b26d30d7328
3. be9c81c298e350466c85eda3eecb1da351e8531a5faac71a7a836c4dd03ec7ae

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.