Every round is dealt from HMAC-SHA256(server seed, client seed : nonce : block). You are given SHA-256(server seed) before you play, so the server seed is locked in and cannot be changed once you know your board. Reveal the seed and any round below can be re-dealt from scratch and compared against the fingerprint recorded when it was played.

The board already on the table is fingerprinted the moment it is dealt, but the seed that produced it stays sealed until you rotate — note the fingerprint down, then verify it after. Changing the client seed also rotates the server seed and reveals the old one; your seed always changes before the next round is dealt, never after.

Paste a proof JSON copied from any round (yours or someone else's) to re-deal it here.

This build is a single-file demo: the server seed is generated and held in your own browser, so it proves the game engine cannot re-roll a board after you have seen it, but it is not a third-party-attested server commitment. Visual effects (particles, reveal order, sound) use a separate non-committed source and cannot influence any outcome.