(VB.NET) Load PEM ASN.1 and Convert to XML

Loads a CSR (Certificate Signing Request) from PEM and converts the ASN.1 to XML format. The purpose of this example is to compare the ASN.1 format with the corresponding XML. One means for accessing a particular piece of information within any ASN.1 document is to convert to XML, and then use any XML API to extract the required data.

The PEM used in this example may be downloaded here: Sample CSR PEM

It contains ASN.1 with this format:

After converting, the XML looks like this:

<?xml version="1.0" encoding="utf-8" ?>
<sequence>
    <sequence>
        <int>00</int>
        <sequence>
            <set>
                <sequence>
                    <oid>2.5.4.6</oid>
                    <printable>US</printable>
                </sequence>
            </set>
            <set>
                <sequence>
                    <oid>2.5.4.8</oid>
                    <utf8>Utah</utf8>
                </sequence>
            </set>
            <set>
                <sequence>
                    <oid>2.5.4.7</oid>
                    <utf8>Lindon</utf8>
                </sequence>
            </set>
            <set>
                <sequence>
                    <oid>2.5.4.10</oid>
                    <utf8>DigiCert Inc.</utf8>
                </sequence>
            </set>
            <set>
                <sequence>
                    <oid>2.5.4.11</oid>
                    <utf8>DigiCert</utf8>
                </sequence>
            </set>
            <set>
                <sequence>
                    <oid>2.5.4.3</oid>
                    <utf8>example.digicert.com</utf8>
                </sequence>
            </set>
        </sequence>
        <sequence>
            <sequence>
                <oid>1.2.840.113549.1.1.1</oid>
                <null />
            </sequence>
            <bits n="2160">3082010A0282010... </bits>
        </sequence>
        <contextSpecific tag="0" constructed="1" />
    </sequence>
    <sequence>
        <oid>1.2.840.113549.1.1.5</oid>
        <null />
    </sequence>
    <bits n="2048">1D2472B15C7129850E6...  </bits>
</sequence>

Chilkat .NET Downloads Chilkat .NET Framework Chilkat for .NET Core

'  Starting in v9.5.0.49, all Chilkat classes can be unlocked at once at the beginning of a program
'  by calling UnlockBundle.  It requires a Bundle unlock code.
Dim chilkatGlob As New Chilkat.Global
Dim success As Boolean = chilkatGlob.UnlockBundle("Anything for 30-day trial.")
If (success <> True) Then
    Debug.WriteLine(chilkatGlob.LastErrorText)
    Exit Sub
End If


Dim pem As New Chilkat.Pem

'  Load the PEM file.  The password is ignored because it is not an encrypted PEM.
Dim password As String = "notRequired"
success = pem.LoadPemFile("qa_data/asn/sampleCsr.pem",password)

'  Get the CSR in base64 format:
Dim itemType As String = "csr"
Dim itemSubType As String = ""
Dim encoding As String = "base64"
Dim index As Integer = 0
Dim csrBase64 As String = pem.GetEncodedItem(itemType,itemSubType,encoding,index)

'  Load the CSR base64 string into the ASN object
Dim asnRoot As New Chilkat.Asn

success = asnRoot.LoadEncoded(csrBase64,"base64")
If (success <> True) Then
    Debug.WriteLine(asnRoot.LastErrorText)
    Exit Sub
End If


'  Get the ASN.1 in (Chilkat's) XML format:
Dim asnXml As String = asnRoot.AsnToXml()

'  The XML returned by AsnToXml is one long difficult-to-read string
'  with no linebreaks.  It is meant to be compact.
'  To get the XML in pretty, human-readable, indented form,
'  load into the Chilkat XML object an then retrieve:
Dim xmlObj As New Chilkat.Xml
success = xmlObj.LoadXml(asnXml)
asnXml = xmlObj.GetXml()

Debug.WriteLine(asnXml)