title: Error Id: CS0234, Error: The type or namespace name 'Xml' does not exist in the namespace 'System.Security.Cryptography'
body: <p>I am using an online IDE (http://www.frosthawk.net/) to run my C# code and upon compilation I get the error </p>
  
  <p>Error Id: CS0234, Error: The type or namespace name 'Xml' does not exist in the namespace 'System.Security.Cryptography' (are you missing an assembly reference?), Line: 26, Column: 36</p>
  
  <p>Can anybody tell me how to add this reference to my code whicle using the the online IDE as I cannot right click and Add Reference that we used to do normally</p>
  
  <pre><code>    using System;
      using System.Security.Cryptography;
      using System.Security.Cryptography.X509Certificates;
      using System.Security.Cryptography.Xml;
      using System.Text;
      using System.Xml;
  
      public class SignVerifyEnvelope
      {
  
       public static void Main(String[] args)
      {
      try
      {
  
       ......
  </code></pre>