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

0c61d17f630965a34d0e7b476faff0baf6976aaed7b096b4708ee6a35c5cded4

Seed

25b12cd2f32ec3660e8b4b4d8903d68a5feff1f8fd4a53d9220ce724ca710e96 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

07559450aa1ac95dbd36307d9185a583

Commitment

Batch 56,290, Merkle root a6b45d0fd86f772384d27ec918b72b32163d34ffe96b21b979138063c27fa6c5. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 96a09d12366bb04ab418fe4e668cc75450a794ed5416caf1212c0f8707add8d2

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.