When you play a game you can pass an extra custom string – client seed (if it’s not specified a random number is automatically generated by your browser). The server will then calculate another hash using the server secret, the server seed and the client seed. The last 5 chars of this hash (representing a hexadecimal value) will be converted to an integer. The result number will be used to adjust the initial toss. Because the client seed can not be predicted by the server the adjustment is completely random and hence you can be sure that the game result is fair.