(Visual Basic 6.0) Get Certificates within XML Signature

Demonstrates how to get the certificates contained within an XML signature.

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

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

Dim sbXml As New ChilkatStringBuilder

' Load XML containing one or more signatures.
Dim success As Long
success = sbXml.LoadFile("qa_data/xml_dsig_valid_samples/multipleSigners/sp.pdf.XAdES.xml","utf-8")
If (success = 0) Then
    Debug.Print "Failed to load the XML file.."
    Exit Sub
End If

Dim dsig As New ChilkatXmlDSig

' First load the XML containing the signatures to be verified.
' Note that this particular Signature already contains the RSA public key that will be used
' for verification.
success = dsig.LoadSignatureSb(sbXml)
If (success <> 1) Then
    Debug.Print dsig.LastErrorText
    Exit Sub
End If

' For each signature, verify and also get the certificate(s) contained within each Signature.
Dim i As Long
i = 0
Dim saCerts As New CkStringArray
Dim cert As New ChilkatCert

Debug.Print "numSignatures = " & dsig.NumSignatures

Do While i < dsig.NumSignatures
    ' Select the Nth signature by setting the Selector property.
    dsig.Selector = i

    Dim bVerifyReferenceDigests As Long
    bVerifyReferenceDigests = 1
    Dim bVerified As Long
    bVerified = dsig.VerifySignature(bVerifyReferenceDigests)
    Debug.Print "Signature " & (i + 1) & " verified = " & bVerified

    ' Get the certificates embedded in this signature.
    saCerts.Clear 
    success = dsig.GetCerts(saCerts)
    If (success = 1) Then
        Dim j As Long
        j = 0
        Do While j < saCerts.Count
            success = cert.LoadFromBase64(saCerts.GetString(j))
            If (success = 1) Then
                Debug.Print "    " & cert.SubjectDN
            End If

            j = j + 1
        Loop
    End If

    i = i + 1
Loop