using System.Net.NetworkInformation;

public string GetMacAddress()
        {
            string physicalAddress = "";
            NetworkInterface[] nice = NetworkInterface.GetAllNetworkInterfaces();
            foreach (NetworkInterface adaper in nice)
            {
                if (adaper.Description == "en0")
                {
                    physicalAddress = adaper.GetPhysicalAddress().ToString();
                    break;
                }
                else
                {
                    physicalAddress = adaper.GetPhysicalAddress().ToString();
                    if (physicalAddress != "")
                    {
                        break;
                    };
                }
            }
            return physicalAddress;
        }