Verify Dice
Dice is the simplest provably-fair game: a single float drives a roll between 0.00 and 100.00. Faircheck regenerates that exact float from your server seed, client seed and nonce, so you can confirm the roll the casino showed you was the only roll it could have produced.
The algorithm
A single 4-byte float is taken from the HMAC-SHA256 byte stream keyed by your server seed.
The float (a number in [0, 1)) is multiplied by 10001 and floored, then divided by 100 to give a roll with two decimals between 0.00 and 100.00.
Because the server seed was committed to as a SHA-256 hash before the bet, the operator could not change it after seeing your client seed or nonce.
FAQ
Why 10001 and not 10000?
Multiplying by 10001 makes every roll from 0.00 to 100.00 inclusive equally likely once floored — using 10000 would make 100.00 unreachable.
My roll does not match. What now?
Check the nonce (it increments by one each bet) and that you pasted the UNHASHED server seed the casino revealed after rotating your seed pair. A single wrong character changes everything.
Verify Dice on your casino
The math is the same everywhere, but each page is tuned to how that casino reveals its seeds.