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

b756d7e2fea3d4aa81aa911276e8377b6746c99b683949de50dbadf7e9d48755

Seed

5e843b30663cd064b8f52ef7b0d9fd181f1948fad2af026908ca217c7f36ddd0 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

b08f87e80d3a4c8ea1862f8421054daf

Commitment

Batch 72,511, Merkle root 5547f4744541a26bb8648763913db1bc82700bd35211ee8371138c91d91ef238. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 796417d5484bdcbd641150c1488e878d9d0fb059bbc0d8389b70ed459b00f853
2. 63b2b611496246b8c45ceebc4cb90c15ffd4e06eb4cb10b95b7fb9f12856a8ca

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.