Авторизация на сайте через сертификат

Dim xmlHttp As Object
Dim Sert As String = "HKEY_LOCAL_MACHINE\...."
Dim StCode As Integer
xmlHttp = CreateObject("WinHttp.WinHttpRequest.5.1") 
xmlHttp.SetClientCertificate(Sert) 
xmlHttp.Open("GET", "https:...", False)
xmlHttp.Send()
StCode = xmlHttp.Status

Class MyWebClient
    Inherits WebClient
 
    Protected Overrides Function GetWebRequest(address As Uri) As WebRequest
        Dim request As WebRequest = MyBase.GetWebRequest(address)
        If TypeOf request Is HttpWebRequest Then
            Dim httpRequest As HttpWebRequest = DirectCast(request, HttpWebRequest)
            Dim certificate As X509Certificate = ... ' Получаем сертификат
            httpRequest.ClientCertificates.Add(certificate)
        End If
        Return request
    End Function
End Class

Dim req As MyWebClient
req.GetWebRequest("https...")

Dim certificate As X509Certificate = "HKEY_LOCAL_MACHINE..."

Dim req As New MyWebClient

    Friend Function GetPage(byVal url as String) as String
        ServicePointManager.ServerCertificateValidationCallback = Function(sender, certificate, chain, sslPolicyErrors) True
        
        Dim getReg As HttpWebRequest = WebRequest.Create(url)
        getReg.Method = "GET"
        getReg.ContentType = "text/html"
        getReg.UserAgent = "Mozilla/5.0 (Windows; U; Windows NT 6.1; ru; rv:1.9.2.12) Gecko/20101026 Firefox/3.6.12"
 
        Dim respPage As String = ""
        Dim postReqReader As StreamReader = Nothing
        Dim postresponse As HttpWebResponse = getReg.GetResponse()
        postReqReader = New StreamReader(postresponse.GetResponseStream, System.Text.Encoding.UTF8)
        respPage = postReqReader.ReadToEnd()
 
        postresponse.Close()
        postReqReader.Close()
        
    Return respPage
    End Function

Dim cert As String = "d:\123.cer"
 Dim certificate As New X509Certificate(cert)

 Dim req As New MyWebClient
 req.DownloadFile()