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

b94d23d0400dab00451925639536daa69fdf252da06875fe3dd00ac51562f813

Seed

ccbb196e436c5415a5d0b90dc70816c1925e939bd8b0e8d7b36f63f6ac38cb10 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

da343b74c8745b26ca1f32d73e63e3a4

Commitment

Batch 63,479, Merkle root c07a7062eb3b99f5022fd628bb15d16b9ba425ff443ab7d882519715a22aab18. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 35ad9953182c5e7a5d2142573a3eb8f6b2044f3ced4ac129dfa0d245152beb24
2. ac565b77596b6827e29f66c898e0e6ec5a82fe3bd41c655c28ff9940a80c67cf

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.