/// <summary>
 /// DeleteKeys method implementation
 /// </summary>
 private void DeleteKeys()
 {
     foreach (Control ctrl in this.WebAuthN.Controls)
     {
         if (ctrl is CheckBox)
         {
             CheckBox box = ctrl as CheckBox;
             if (box.Checked)
             {
                 MMCService.RemoveUserStoredCredentials(_upn, box.Tag.ToString());
             }
         }
     }
 }