1. A secret server seed is generated, and you're shown its SHA-256 hash up front. The hash locks the seed in without revealing it.
2. You pick a client seed (or keep the random one). Each round adds a nonce that counts up by one.
3. Each round computes HMAC-SHA256(server, "client:nonce:cursor"). Every 4 bytes become a number between 0 and 1, which the game turns into cards, reel stops, a pocket or a crash point.
4. When you rotate, the old server seed is revealed. Hash it to confirm it matches what you were shown, then verify any past round below.

Honest note: right now seeds are generated and stored in your browser, because AFTERGLOW has no accounts yet. That makes this a transparency tool rather than proof against the house. When cloud accounts arrive, the server seed will be committed by our server.