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

01591553dd762626f70f89b4f83722f54adbe9269207694cc8a6ee54d29a0a8a

Seed

4fd7a3196fa1cffb4e91c59d336443610f727a4702291d3ac9ce472ef8f901a2 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

b07c0a222d29c3d5ad1bff222a51f6e2

Commitment

Batch 51,364, Merkle root 736a6701e508ef6c7bc2cfd01a5d8fcaf2341316b4cce26b54b81dc31ed13bc2. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 4886a8dd10ca457e6cc3fa649c4b72612a6f40840cbaa21842d45ff0bbb41c34
2. e2c80a25c2074f03fe6e46b29a683fcc93576d471a283a04c733190a19363500
3. 3e94dd989995fdb4ff7952156f7cc74fe656fc160b750dbe616a0ada4b3b35bb

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.