Use the AsnEncodedDataCollection class. : AsnEncodedDataCollection « Security « C# / CSharp Tutorial

1. C# / CSharp Tutorial
2. Security
3. AsnEncodedDataCollection

using System;
using System.Security.Cryptography;
using System.Security.Cryptography.X509Certificates;

class MainClass
{
    static void Main()
    {        
            X509Store store = new X509Store("MY", StoreLocation.CurrentUser);
            store.Open(OpenFlags.ReadOnly | OpenFlags.OpenExistingOnly);
            X509Certificate2Collection collection = (X509Certificate2Collection)store.Certificates;
            X509Certificate2Collection fcollection = (X509Certificate2Collection)collection.Find(X509FindType.FindByTimeValid, DateTime.Now, false);

            X509Certificate2Collection scollection = X509Certificate2UI.SelectFromCollection(fcollection, "Certificate Select", "Select certificates from the following list to get extension information on that certificate", X509SelectionFlag.MultiSelection);

            AsnEncodedDataCollection asncoll = new AsnEncodedDataCollection();
            for (int i = 0; i < scollection.Count; i++)
            {
                Console.WriteLine( scollection[i].GetName());
                foreach (X509Extension extension in scollection[i].Extensions)
                {
                    AsnEncodedData asndata = new AsnEncodedData(extension.Oid, extension.RawData);
                    Console.WriteLine(extension.Oid.FriendlyName);
                    Console.WriteLine(asndata.Oid.Value);
                    Console.WriteLine(asndata.RawData.Length);
                    Console.WriteLine(asndata.Format(true));
                    asncoll.Add(asndata);
                }
            }
            Console.WriteLine(asncoll.Count);
            store.Close();
            AsnEncodedDataEnumerator asne = asncoll.GetEnumerator();
            asne.MoveNext();

            Console.WriteLine(asne.Current.Format(true));
            asne.MoveNext();
            Console.WriteLine(asne.Current.Format(true));
            asne.Reset();
    }
}