Visual Basic 6.0

Load PEM ASN.1 and Convert to XML

See more ASN.1 Examples

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>

Visual Basic 6.0

Dim success As Long
success = 0

' This example assumes the Chilkat API to have been previously unlocked.
' See Global Unlock Sample for sample code.

success = 0

Dim pem As New ChilkatPem

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

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

' Load the CSR base64 string into the ASN object
Dim asnRoot As New ChilkatAsn

success = asnRoot.LoadEncoded(csrBase64,"base64")
If (success <> 1) Then
    Debug.Print asnRoot.LastErrorText
    Exit Sub
End If

' Get the ASN.1 in (Chilkat's) XML format:
Dim asnXml As String
asnXml = 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 ChilkatXml
success = xmlObj.LoadXml(asnXml)
asnXml = xmlObj.GetXml()

Debug.Print asnXml