(PureBasic) Get Certificates within XML Signature

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

Chilkat PureBasic Module Download Chilkat PureBasic Module

IncludeFile "CkCert.pb"
IncludeFile "CkStringBuilder.pb"
IncludeFile "CkXmlDSig.pb"
IncludeFile "CkStringArray.pb"

Procedure ChilkatExample()

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

    sbXml.i = CkStringBuilder::ckCreate()
    If sbXml.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ; Load XML containing one or more signatures.
    success.i = CkStringBuilder::ckLoadFile(sbXml,"qa_data/xml_dsig_valid_samples/multipleSigners/sp.pdf.XAdES.xml","utf-8")
    If success = 0
        Debug "Failed to load the XML file.."
        CkStringBuilder::ckDispose(sbXml)
        ProcedureReturn
    EndIf

    dsig.i = CkXmlDSig::ckCreate()
    If dsig.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ; 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 = CkXmlDSig::ckLoadSignatureSb(dsig,sbXml)
    If success <> 1
        Debug CkXmlDSig::ckLastErrorText(dsig)
        CkStringBuilder::ckDispose(sbXml)
        CkXmlDSig::ckDispose(dsig)
        ProcedureReturn
    EndIf

    ; For each signature, verify and also get the certificate(s) contained within each Signature.
    i.i = 0
    saCerts.i = CkStringArray::ckCreate()
    If saCerts.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    cert.i = CkCert::ckCreate()
    If cert.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    Debug "numSignatures = " + Str(CkXmlDSig::ckNumSignatures(dsig))

    While i < CkXmlDSig::ckNumSignatures(dsig)
        ; Select the Nth signature by setting the Selector property.
        CkXmlDSig::setCkSelector(dsig, i)

        bVerifyReferenceDigests.i = 1
        bVerified.i = CkXmlDSig::ckVerifySignature(dsig,bVerifyReferenceDigests)
        Debug "Signature " + Str(i + 1) + " verified = " + Str(bVerified)

        ; Get the certificates embedded in this signature.
        CkStringArray::ckClear(saCerts)
        success = CkXmlDSig::ckGetCerts(dsig,saCerts)
        If success = 1
            j.i = 0
            While j < CkStringArray::ckCount(saCerts)
                success = CkCert::ckLoadFromBase64(cert,CkStringArray::ckGetString(saCerts,j))
                If success = 1
                    Debug "    " + CkCert::ckSubjectDN(cert)
                EndIf

                j = j + 1
            Wend
        EndIf

        i = i + 1
    Wend


    CkStringBuilder::ckDispose(sbXml)
    CkXmlDSig::ckDispose(dsig)
    CkStringArray::ckDispose(saCerts)
    CkCert::ckDispose(cert)


    ProcedureReturn
EndProcedure