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

858ed5ff832bca8f657eb2918e49fe598d5f54c97a02f84c5e0153b44a23ab20

Seed

3e197f85a7502a77cb530ff75af46e4b293c806537cc75034fc7f5be309644e7 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

978c7e8f8bf7a0b892a5d9bb2e10ec86

Commitment

Batch 70,193, Merkle root c4d6eb1c81ca66454cf8335516a077b39c8f46b80f944cc562a045bd35ceb6a8. Recorded by Degen Protocol; on-chain publication is not available yet. See this batch and its Merkle tree

Merkle path

1. 692d9fcb06d6c4c92fa57fcac0ee8648643826ac7f4824c7703894d79639c9d1
2. 516fdca8f781c9f7b1028555afb79626ad8c56f8a687c10de41f32fde9977c7d

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.