public static string RandomizeString(string str)
{
var chars = str.ToArray();
var random = new Random();
for(int n = chars.Length-1; n>=0; n--)
{
var randomNumber = random.Next(chars.Length);
var savedChar = chars[randomNumber];
chars[randomNumber] = chars[n];
chars[n] = savedChar;
}
return new string(chars);
}