Fairness

Each Mines board is locked in when the round starts. It comes from three values:

• Client seed. Text you can read anytime. Type a new one, or leave the box empty and press Change client seed to get a random one.
• Server seed. A long random string kept on the server. It mixes letters, numbers, and symbols such as + and /. Until you change your client seed, you only see its SHA-256 hash.
• Nonce. A counter. It starts at 1 and goes up by one every time a Mines, Dice, or Limbo round starts.

Server seeds written in blue are still hashed. You cannot turn the blue text back into the real seed, so those plays cannot be checked yet. Change your client seed after the open round is finished. The old server seed is then shown in the normal text color, and you can verify every play that used it. A new blue hash is published for the next rounds, and the nonce starts again at 1.

The change waits until your current Mines round is over. Showing the real server seed while tiles are still closed would show where the mines are.

To check a finished play, open this code. It joins the server seed, client seed, and nonce with hyphens, hashes that with HMAC-SHA256, and shuffles the board the same way the round was created. Replace the four values at the top with the finished round, then press Run.