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

e31899c43689816c355ee3220671bc04c889b11977dc7617d488b5c597cfa40f

Seed

64b34ba66616c166ff0dc1b8d5b932e8f741800c0f572889bb017f41e4f37e9b SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

4761958292a54ae161ceb10463c500f3

Commitment

Batch 54,818, Merkle root e9768fb7b72cb268455e9a81224785c1008bcd6203e3e713facd8381bad35679. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 9a5fbc17b2bc20b25cf09c171026dff9c7de857832a6dec856953f1765570712
2. 9e4f801c38c3f7df305ddf90178b9050eb9e5ace7740667a2d005d4af3a704ce

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.