Extract integer serial from x509SerialNumber hex in certificate

The important thing here is to trim leading zeros that serve just for filling data into byte octets.

04CF = 4CF
4CF(hex) = 1231 (int)

Accessing the certificate serial number can be done in many ways. This is just an example.

//Load certificate
X509Certificate2 _certificate = new X509Certificate2("C:\mycert.p12");

//Extract serial number and trim leading zeros
String serialHex = _certificate.SerialNumber.TrimStart('0');

//Convert from hex to integer (im converting it also to string)
String serialInteger = int.Parse(serialHex, NumberStyles.HexNumber).ToString();