Parse X509Certificate SAN extensions

X509SANExtensionParse.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.ServiceModel;
using System.ServiceModel.Channels;
using System.Text;
using System.Threading.Tasks;
using System.Security.Cryptography.X509Certificates;
using System.ServiceModel.Security;
using System.Security.Authentication;
using System.Net;

namespace ConsoleApplication1
{
    class Program
    {
        public static void Main()
        {
            const string x509ExtensionBase64String = "MD2CFW5vdC1yZWFsLXN1YmplY3QtbmFtZYIZbm90LXJlYWwtZnFkbi5leGFtcGxlLmNvbYIJbG9jYWxob3N0";
            const string subjectName1 = "not-real-subject-name";

            X509Extension x509Extension = new X509Extension("2.5.29.17", Convert.FromBase64String(x509ExtensionBase64String), true);
            string x509ExtensionFormattedString = x509Extension.Format(false);

            // On Windows, x509ExtensionFormattedString is: 
            // DNS Name=not-real-subject-name, DNS Name=not-real-fqdn.example.com, DNS Name=localhost

            // <identifier><delimter><value><separator(s)>
            int delimiterIndex = x509ExtensionFormattedString.IndexOf(subjectName1) - 1;
            char delimiter = x509ExtensionFormattedString[delimiterIndex];
            string identifier = x509ExtensionFormattedString.Substring(0, delimiterIndex);

            int separatorFirstChar = delimiterIndex + subjectName1.Length + 1;
            int separatorLength = 1;
            for (int i = separatorFirstChar + 1; i < x509ExtensionFormattedString.Length; i++)
            {
                if (x509ExtensionFormattedString[i] == identifier[0])
                {
                    break;
                }
                else
                {
                    separatorLength++;
                }
            }

            Console.WriteLine(x509Extension); 

            Console.WriteLine("done.");
            Console.Read(); 
        }
    }
}