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

dd946af57eaa17a5336d47faed6bcdeabc834f5d1e9208e22e53094fab2e57af

Seed

5616130286a43696d5b056ba1586e135e4b55d769875160f498ae3c28e1652fc SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

fe6c217cce43bdd5bd7a6daa516f5b7a

Commitment

Batch 62,227, Merkle root 60020d3b41b0375c64db024a3a3adf3f397f22c1e6b2beebae51713424d75b3b. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 9185b26bba3c6736cc69da7c2a3a7fffcd9e53612c22744f029f7fba964cf166
2. ac12cff9578d725e5e4f8e575350c58bb0bba7f2ec1aac9e7ab40c92782e2546
3. 7924af18009eceb86176f6e1defbd76a7f7ecb9ae5ac147ae5e3b20472fc4afe

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.