public bool Decode(string barCode, string token, out long uid)
{
long cat = Convert.ToInt64(barCode.Substring(prefix.Length));
uid = cat / n;
long pwd = cat % n;
DynamicPassword otp = new DynamicPassword(token, duration);
return(otp.Verify(pwd.ToString()));
}
public string Encode(long uid, string token)
{
DynamicPassword otp = new DynamicPassword(token, duration);
string pwd = otp.GetPassword(n.ToString().Length - 1);
long l = Convert.ToInt64(pwd);
long res = uid * n + l;
return(prefix + res.ToString().PadLeft(16, '0'));
}