(PowerBuilder) Create XML Signature with External XML Reference

Demonstrates how to create an XML digital signature where the referenced data is external. In this case, the data is an XML file located at the following URL: https://www.chilkatsoft.com/data/helloWorld.xml

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

integer li_rc
oleobject loo_Xml
oleobject loo_Cert
integer li_Success
oleobject loo_Gen
oleobject loo_Http
oleobject loo_SbExternalXml
integer li_BUsePrivateKey
oleobject loo_SbXml
oleobject loo_Verifier
oleobject loo_SbExternalData
integer li_NumRefs
integer i
integer li_BExternal
string ls_Uri
string ls_CanonXml
integer li_BVerified

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

// This example inserts an XML signature in the following XML:

// <?xml version="1.0" encoding="UTF-8" standalone="no"?>
// <abc>
//   <xyz>
// 	<name>helloWorld.xml</name>
// 	<url>https://www.chilkatsoft.com/data/helloWorld.xml</url>
//   </xyz>
// </abc>

// Build the above XML to be signed.
loo_Xml = create oleobject
// Use "Chilkat_9_5_0.Xml" for versions of Chilkat < 10.0.0
li_rc = loo_Xml.ConnectToNewObject("Chilkat.Xml")
if li_rc < 0 then
    destroy loo_Xml
    MessageBox("Error","Connecting to COM object failed")
    return
end if
loo_Xml.Tag = "abc"
loo_Xml.UpdateChildContent("xyz|name","helloWorld.xml")
loo_Xml.UpdateChildContent("xyz|url","https://www.chilkatsoft.com/data/helloWorld.xml")

loo_Cert = create oleobject
// Use "Chilkat_9_5_0.Cert" for versions of Chilkat < 10.0.0
li_rc = loo_Cert.ConnectToNewObject("Chilkat.Cert")

li_Success = loo_Cert.LoadPfxFile("qa_data/pfx/test_secret.pfx","secret")
if li_Success = 0 then
    Write-Debug loo_Cert.LastErrorText
    destroy loo_Xml
    destroy loo_Cert
    return
end if

loo_Gen = create oleobject
// Use "Chilkat_9_5_0.XmlDSigGen" for versions of Chilkat < 10.0.0
li_rc = loo_Gen.ConnectToNewObject("Chilkat.XmlDSigGen")

// Indicate the location within the XML the Signature will be inserted.
loo_Gen.SigLocation = "abc|xyz"

// Get the content of the XML data to be referenced.
loo_Http = create oleobject
// Use "Chilkat_9_5_0.Http" for versions of Chilkat < 10.0.0
li_rc = loo_Http.ConnectToNewObject("Chilkat.Http")

loo_SbExternalXml = create oleobject
// Use "Chilkat_9_5_0.StringBuilder" for versions of Chilkat < 10.0.0
li_rc = loo_SbExternalXml.ConnectToNewObject("Chilkat.StringBuilder")

li_Success = loo_Http.QuickGetSb("https://www.chilkatsoft.com/data/helloWorld.xml",loo_SbExternalXml)
if li_Success = 0 then
    Write-Debug loo_Http.LastErrorText
    destroy loo_Xml
    destroy loo_Cert
    destroy loo_Gen
    destroy loo_Http
    destroy loo_SbExternalXml
    return
end if

li_Success = loo_Gen.AddExternalXmlRef("https://www.chilkatsoft.com/data/helloWorld.xml",loo_SbExternalXml,"sha256","EXCL_C14N","")
if li_Success = 0 then
    Write-Debug loo_Gen.LastErrorText
    destroy loo_Xml
    destroy loo_Cert
    destroy loo_Gen
    destroy loo_Http
    destroy loo_SbExternalXml
    return
end if

// Provide the private key for signing via the certificate, and indicate that
// we want the base64 of the certificate embedded in the KeyInfo.
loo_Gen.KeyInfoType = "X509Data"
loo_Gen.X509Type = "Certificate"

li_BUsePrivateKey = 1
li_Success = loo_Gen.SetX509Cert(loo_Cert,li_BUsePrivateKey)
if li_Success <> 1 then
    Write-Debug loo_Gen.LastErrorText
    destroy loo_Xml
    destroy loo_Cert
    destroy loo_Gen
    destroy loo_Http
    destroy loo_SbExternalXml
    return
end if

// Indicate we want an indented signature for readability.
// This can be removed after debugging is finished..
loo_Gen.Behaviors = "IndentedSignature"

// Now create and insert the Signature
loo_SbXml = create oleobject
// Use "Chilkat_9_5_0.StringBuilder" for versions of Chilkat < 10.0.0
li_rc = loo_SbXml.ConnectToNewObject("Chilkat.StringBuilder")

loo_Xml.GetXmlSb(loo_SbXml)
li_Success = loo_Gen.CreateXmlDSigSb(loo_SbXml)
if li_Success <> 1 then
    Write-Debug loo_Gen.LastErrorText
    destroy loo_Xml
    destroy loo_Cert
    destroy loo_Gen
    destroy loo_Http
    destroy loo_SbExternalXml
    destroy loo_SbXml
    return
end if

// Examine the XML with the digital signature inserted
Write-Debug loo_SbXml.GetAsString()

// Here is the output:

// <?xml version="1.0" encoding="utf-8"?>
// <abc>
//     <xyz>
//         <name>helloWorld.xml</name>
//         <url>https://www.chilkatsoft.com/data/helloWorld.xml</url>
//     <ds:Signature xmlns:ds="http://www.w3.org/2000/09/xmldsig#">
//   <ds:SignedInfo>
//     <ds:CanonicalizationMethod Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#"/>
//     <ds:SignatureMethod Algorithm="http://www.w3.org/2001/04/xmldsig-more#rsa-sha256"/>
//     <ds:Reference URI="https://www.chilkatsoft.com/data/helloWorld.xml">
//       <ds:Transforms>
//         <ds:Transform Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#"/>
//       </ds:Transforms>
//       <ds:DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256"/>
//       <ds:DigestValue>H/s775OZhel6wdBhe02l4LK6m0lkplOisKxAbVwWxp0=</ds:DigestValue>
//     </ds:Reference>
//   </ds:SignedInfo>
//   <ds:SignatureValue>UruwnBqh..Ll4IzUA==</ds:SignatureValue>
//   <ds:KeyInfo>
//     <ds:X509Data>
//       <ds:X509Certificate>MIIHAz...nUZWCaDE=</ds:X509Certificate>
//     </ds:X509Data>
//   </ds:KeyInfo>
// </ds:Signature></xyz>
// </abc>

// Let's verify the signature...
loo_Verifier = create oleobject
// Use "Chilkat_9_5_0.XmlDSig" for versions of Chilkat < 10.0.0
li_rc = loo_Verifier.ConnectToNewObject("Chilkat.XmlDSig")

li_Success = loo_Verifier.LoadSignatureSb(loo_SbXml)
if li_Success <> 1 then
    Write-Debug loo_Verifier.LastErrorText
    destroy loo_Xml
    destroy loo_Cert
    destroy loo_Gen
    destroy loo_Http
    destroy loo_SbExternalXml
    destroy loo_SbXml
    destroy loo_Verifier
    return
end if

// Let's examine the external references, and fetch the data for each..
loo_SbExternalData = create oleobject
// Use "Chilkat_9_5_0.StringBuilder" for versions of Chilkat < 10.0.0
li_rc = loo_SbExternalData.ConnectToNewObject("Chilkat.StringBuilder")

li_NumRefs = loo_Verifier.NumReferences
i = 0
do while i < li_NumRefs
    li_BExternal = loo_Verifier.IsReferenceExternal(i)
    if li_BExternal = 1 then
        ls_Uri = loo_Verifier.ReferenceUri(i)

        // We're assuming the URI is an https:// or http:// URL...
        // Let's also assume we know that the referenced data is text and we want the utf-8 byte representation.
        loo_SbExternalData.Clear()
        li_Success = loo_Http.QuickGetSb(ls_Uri,loo_SbExternalData)
        if li_Success = 0 then
            Write-Debug loo_Http.LastErrorText
            destroy loo_Xml
            destroy loo_Cert
            destroy loo_Gen
            destroy loo_Http
            destroy loo_SbExternalXml
            destroy loo_SbXml
            destroy loo_Verifier
            destroy loo_SbExternalData
            return
        end if

        // Because the referenced external data was explicitly XML, it was the canonicalized XML that was digested.
        // We need to canonicalize the XML in the same way as when signed.
        ls_CanonXml = loo_Verifier.CanonicalizeXml(loo_SbExternalData.GetAsString(),"EXCL_C14N",0)
        loo_SbExternalData.SetString(ls_CanonXml)

        li_Success = loo_Verifier.SetRefDataSb(i,loo_SbExternalData,"utf-8")
        if li_Success = 0 then
            Write-Debug loo_Verifier.LastErrorText
            destroy loo_Xml
            destroy loo_Cert
            destroy loo_Gen
            destroy loo_Http
            destroy loo_SbExternalXml
            destroy loo_SbXml
            destroy loo_Verifier
            destroy loo_SbExternalData
            return
        end if

    end if

    i = i + 1
loop

// Now that we have the external data available, we can verify the reference digest(s) and the signature.
li_BVerified = loo_Verifier.VerifySignature(1)
if li_BVerified <> 1 then
    Write-Debug loo_Verifier.LastErrorText
    destroy loo_Xml
    destroy loo_Cert
    destroy loo_Gen
    destroy loo_Http
    destroy loo_SbExternalXml
    destroy loo_SbXml
    destroy loo_Verifier
    destroy loo_SbExternalData
    return
end if

Write-Debug "Signature verified!"


destroy loo_Xml
destroy loo_Cert
destroy loo_Gen
destroy loo_Http
destroy loo_SbExternalXml
destroy loo_SbXml
destroy loo_Verifier
destroy loo_SbExternalData