Using pfx certificate to authenticate a webrequest

Discussion in 'ASP .Net' started by Nelson R., Jan 5, 2005.

  1. Nelson R.

    Nelson R. Guest


    i need to get some info from a website page that requires an

    Ive got the provided certificate installed in IE, and when accessing
    the website page, it shows a window to select the client certificate
    and then shows the page correctly.

    Im trying to do this by code (vs2003 C# aspnet), using webrequest.

    The certificate is in an pfx file and does not require password. I've
    exported the file using IE to DER encoded binary X.509 (.cer), since
    its the only format used by .net webrequest certificates (?)

    My code:

    X509Certificate certificate =
    HttpWebRequest req =

    // ...
    // here goes the request response read
    // ...

    I got this error:

    System.Net.WebException: The underlying connection was closed: Could
    not establish secure channel for SSL/TLS. --->
    System.ComponentModel.Win32Exception: The message received was
    unexpected or badly formatted at
    System.Net.TlsStream.EndRead(IAsyncResult asyncResult) at
    System.Net.Connection.ReadCallback(IAsyncResult asyncResult) --- End
    of inner exception stack trace --- at
    System.Net.HttpWebRequest.CheckFinalStatus() at
    System.Net.HttpWebRequest.EndGetResponse(IAsyncResult asyncResult) at

    From the error i can see that the certificate is invalid, because if i
    dont use the certificate i get the same error messagem.

    So... anyone knows how or point me to the right path to do a request
    from an https website, using an pfx file?

    Best regards,
    Nelson R.
    Nelson R., Jan 5, 2005
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  2. Nelson R.

    Nelson R. Guest


    dont understand why nobody ever answer my questions about using
    certificates in aspnet (this is not my first post about this).

    Well, ive solved my problem. I had an pfx certificate installed and
    exported to x509 format. Using webrequest and the exported certificate
    i was getting an error accessing the website (https)

    The problem was because my ASPNET account didnt have the rights to
    access installed certificate.

    I had to use a microsoft tool (winhttpcertcfg) to give access to
    ASPNET account.

    Tool url:

    Know all works...

    Hope this will help anyone who has the same problem...

    Best regards,
    Nelson R.
    Nelson R., Jan 10, 2005
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  3. Nelson R.


    Sep 25, 2009
    Likes Received:
    help on accessing https website

    How do you download the certficate..where to find the .cer file?
    can you please send me the code for same.

    thanks in advance.
    starter, Sep 25, 2009
  4. Nelson R.


    Mar 21, 2012
    Likes Received:

    Hi Nelson R., I want thank you for your reply... this have help me a lot!!!
    Me too, I have not found relevant help on google or forum in web... :(
    I have not solved my problem completly, but I have seen a way to solve grace your response!!
    Have a nice day!!

    Bye, Roberto
    rmacone, Mar 21, 2012
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