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Xojo Plugin

Signed Zip as Base64 with XAdES-BES

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This example is to help companies implement a solution for sending XAdES-BES to the Polish government for reporting purposes. Specifically:

Przed podpisaniem deklaracja zbiorcza (PIT-11Z, PIT-8CZ, PIT-40Z, PIT-RZ) musi zostać
umieszczona w archiwum ZIP. W tym przypadku, podpisywany jest plik archiwum ZIP,
przyjmujący w podpisie XAdES-BES formę zakodowaną base64.

The example demonstrates the following:

  1. Zip an XML file (PIT-11Z.xml is zipped to PIT-11Z.zip)
  2. Create XML to be signed, where the XML contains the base64 encoded content of the PIT-11Z.zip archive.
  3. XAdES-BES sign the XML containing the base64 zip.

This example will also show the reverse:

  1. Verify the signed XML.
  2. Extract the PIT-11z.zip from the signed XML.
  3. Unzip the PIT-11Z.zip to get the original PIT-11Z.xml

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Dim success As Boolean
success = False

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

// Zip the PIT-11Z.xml to create PIT-11Z.zip (not as a .zip file, but in-memory).
Dim sbXmlToZip As New Chilkat.StringBuilder
success = sbXmlToZip.LoadFile("qa_data/xml/PIT-11Z.xml","utf-8")
If (success <> True) Then
    System.DebugLog("Failed to load the XML to be zipped.")
    Return
End If

Dim zip As New Chilkat.Zip

// Initialize the zip object. No file is created in this call.
// It should always return True.
success = zip.NewZip("PIT-11Z.zip")

// Add the XML to be zipped.
success = zip.AddSb("PIT-11Z.xml",sbXmlToZip,"utf-8")

// Write the zip to a BinData object.
Dim bdZip As New Chilkat.BinData
success = zip.WriteBd(bdZip)
// The contents of the bdZip will be retrieved in base64 format when needed below..

Dim gen As New Chilkat.XmlDSigGen

gen.SigLocation = ""
gen.SigLocationMod = 0

gen.SigId = "Signature_2a8df7f8-b958-40cc-83f6-edb53b837347_19"
gen.SigNamespacePrefix = "ds"
gen.SigNamespaceUri = "http://www.w3.org/2000/09/xmldsig#"
gen.SigValueId = "SignatureValue_2a8df7f8-b958-40cc-83f6-edb53b837347_52"
gen.SignedInfoId = "SignedInfo_2a8df7f8-b958-40cc-83f6-edb53b837347_41"
gen.SignedInfoCanonAlg = "C14N"
gen.SignedInfoDigestMethod = "sha1"

// Set the KeyInfoId before adding references..
gen.KeyInfoId = "KeyInfo_2a8df7f8-b958-40cc-83f6-edb53b837347_24"

// Create an Object to be added to the Signature.
Dim object1 As New Chilkat.Xml
object1.Tag = "xades:QualifyingProperties"
success = object1.AddAttribute("xmlns:xades","http://uri.etsi.org/01903/v1.3.2#")
success = object1.AddAttribute("Id","QualifyingProperties_2a8df7f8-b958-40cc-83f6-edb53b837347_43")
success = object1.AddAttribute("Target","#Signature_2a8df7f8-b958-40cc-83f6-edb53b837347_19")
success = object1.UpdateAttrAt("xades:SignedProperties",True,"Id","SignedProperties_2a8df7f8-b958-40cc-83f6-edb53b837347_4e")
success = object1.UpdateAttrAt("xades:SignedProperties|xades:SignedSignatureProperties",True,"Id","SignedSignatureProperties_2a8df7f8-b958-40cc-83f6-edb53b837347_0a")
// Chilkat will replace the strings "TO BE GENERATED BY CHILKAT" with actual values when the signature is created.
object1.UpdateChildContent "xades:SignedProperties|xades:SignedSignatureProperties|xades:SigningTime","TO BE GENERATED BY CHILKAT"
// Note: It may be that http://www.w3.org/2001/04/xmlenc#sha256 is needed in the following line instead of http://www.w3.org/2000/09/xmldsig#sha1
success = object1.UpdateAttrAt("xades:SignedProperties|xades:SignedSignatureProperties|xades:SigningCertificateV2|xades:Cert|xades:CertDigest|ds:DigestMethod",True,"Algorithm","http://www.w3.org/2000/09/xmldsig#sha1")
object1.UpdateChildContent "xades:SignedProperties|xades:SignedSignatureProperties|xades:SigningCertificateV2|xades:Cert|xades:CertDigest|ds:DigestValue","TO BE GENERATED BY CHILKAT"
object1.UpdateChildContent "xades:SignedProperties|xades:SignedSignatureProperties|xades:SigningCertificateV2|xades:Cert|xades:IssuerSerialV2","TO BE GENERATED BY CHILKAT"
success = object1.UpdateAttrAt("xades:SignedProperties|xades:SignedDataObjectProperties",True,"Id","SignedDataObjectProperties_2a8df7f8-b958-40cc-83f6-edb53b837347_4b")
success = object1.UpdateAttrAt("xades:SignedProperties|xades:SignedDataObjectProperties|xades:DataObjectFormat",True,"ObjectReference","#Reference1_2a8df7f8-b958-40cc-83f6-edb53b837347_27")
object1.UpdateChildContent "xades:SignedProperties|xades:SignedDataObjectProperties|xades:DataObjectFormat|xades:Description","MIME-Version: 1.0" + EndOfLine.Windows + "Content-Type: application/zip" + EndOfLine.Windows + "Content-Transfer-Encoding: binary" + EndOfLine.Windows + "Content-Disposition: filename=&quot;PIT-11Z.zip&quot;"
success = object1.UpdateAttrAt("xades:SignedProperties|xades:SignedDataObjectProperties|xades:DataObjectFormat|xades:ObjectIdentifier|xades:Identifier",True,"Qualifier","OIDAsURI")
object1.UpdateChildContent "xades:SignedProperties|xades:SignedDataObjectProperties|xades:DataObjectFormat|xades:ObjectIdentifier|xades:Identifier","http://www.certum.pl/OIDAsURI/signedFile/1.2.616.1.113527.3.1.1.3.1"
object1.UpdateChildContent "xades:SignedProperties|xades:SignedDataObjectProperties|xades:DataObjectFormat|xades:ObjectIdentifier|xades:Description","Opis formatu dokumentu oraz jego pelna nazwa"
object1.UpdateChildContent "xades:SignedProperties|xades:SignedDataObjectProperties|xades:DataObjectFormat|xades:ObjectIdentifier|xades:DocumentationReferences|xades:DocumentationReference","http://www.certum.pl/OIDAsURI/signedFile.pdf"
object1.UpdateChildContent "xades:SignedProperties|xades:SignedDataObjectProperties|xades:DataObjectFormat|xades:MimeType","application/zip"
object1.UpdateChildContent "xades:SignedProperties|xades:SignedDataObjectProperties|xades:CommitmentTypeIndication|xades:CommitmentTypeId|xades:Identifier","http://uri.etsi.org/01903/v1.2.2#ProofOfApproval"
object1.UpdateChildContent "xades:SignedProperties|xades:SignedDataObjectProperties|xades:CommitmentTypeIndication|xades:AllSignedDataObjects",""
success = object1.UpdateAttrAt("xades:UnsignedProperties",True,"Id","UnsignedProperties_2a8df7f8-b958-40cc-83f6-edb53b837347_55")

// Emit XML in compact (single-line) format to avoid whitespace problems.
object1.EmitCompact = True
success = gen.AddObject("",object1.GetXml(),"","")

// Create an Object to be added to the Signature.
// This is where we add the base64 representation of the PIT-11Z.zip
success = gen.AddObject("Object1_2a8df7f8-b958-40cc-83f6-edb53b837347",bdZip.GetEncoded("base64"),"","http://www.w3.org/2000/09/xmldsig#base64")

// -------- Reference 1 --------
success = gen.AddObjectRef("Object1_2a8df7f8-b958-40cc-83f6-edb53b837347","sha1","C14N_WithComments","","")
success = gen.SetRefIdAttr("Object1_2a8df7f8-b958-40cc-83f6-edb53b837347","Reference1_2a8df7f8-b958-40cc-83f6-edb53b837347_27")

// -------- Reference 2 --------
success = gen.AddObjectRef("SignedProperties_2a8df7f8-b958-40cc-83f6-edb53b837347_4e","sha1","","","http://uri.etsi.org/01903#SignedProperties")
success = gen.SetRefIdAttr("SignedProperties_2a8df7f8-b958-40cc-83f6-edb53b837347_4e","SignedProperties-Reference_2a8df7f8-b958-40cc-83f6-edb53b837347_28")

// Provide a certificate + private key. (PFX password is test123)
Dim cert As New Chilkat.Cert
success = cert.LoadPfxFile("qa_data/pfx/cert_test123.pfx","test123")
If (success = False) Then
    System.DebugLog(cert.LastErrorText)
    Return
End If

success = gen.SetX509Cert(cert,True)

gen.KeyInfoType = "X509Data"
gen.X509Type = "Certificate"

// This will be an enveloping signature where the Signature element
// is the XML document root, the signed data is contained within Object
// tag(s) within the Signature.
// Therefore, pass an empty sbXml to CreateXmlDsigSb.
Dim sbXml As New Chilkat.StringBuilder

// The Polish government's XmlDSig implementation requires that we reproduce an attribute-sorting error.
// (This is an error in the XML canonicalization that is not noticed when both the signature-creation code and signature-verification code use
// the same XML canonicalization implementation w/ the bug.)
gen.Behaviors = "AttributeSortingBug,CompactSignedXml"

// Sign the XML...
success = gen.CreateXmlDSigSb(sbXml)
If (success = False) Then
    System.DebugLog(gen.LastErrorText)
    Return
End If

// -----------------------------------------------

// Save the signed XML to a file.
success = sbXml.WriteFile("qa_output/signedXml.xml","utf-8",False)

System.DebugLog(sbXml.GetAsString())

// ----------------------------------------
// Verify the signature we just produced...
Dim verifier As New Chilkat.XmlDSig
success = verifier.LoadSignatureSb(sbXml)
If (success = False) Then
    System.DebugLog(verifier.LastErrorText)
    Return
End If

Dim verified As Boolean
verified = verifier.VerifySignature(True)
If (verified <> True) Then
    System.DebugLog(verifier.LastErrorText)
    Return
End If

System.DebugLog("This signature was successfully verified.")

// ------------------------------------
// Finally, let's extract the .zip from the signed XML, and then unzip the original PIT-11Z.xml from the in-memory zip.
Dim xml As New Chilkat.Xml
success = xml.LoadSb(sbXml,True)

// The base64 image of the PIT-11Z.zip is in the 2nd ds:Object child of the ds:Signature (the ds:Signature is the root element of the signed XML).
// (ds:Object[0] would be the 1st ds:Object child.  Index 1 is the 2nd ds:Object child.)
Dim strZipBase64 As String
strZipBase64 = xml.GetChildContent("ds:Object[1]")

success = bdZip.Clear()
success = bdZip.AppendEncoded(strZipBase64,"base64")
If (bdZip.NumBytes = 0) Then
    System.DebugLog("Something went wrong.. we dont' have any data..")
    Return
End If

success = zip.OpenBd(bdZip)
If (success = False) Then
    System.DebugLog(zip.LastErrorText)
    Return
End If

// Get the 1st file in the zip, which should be the PIT-11Z.xml
Dim entry As New Chilkat.ZipEntry
success = zip.EntryAt(0,entry)
If (success = False) Then
    System.DebugLog("Zip contains no files...")
    Return
End If

// Get the XML:
Dim origXml As String
origXml = entry.UnzipToString(0,"utf-8")
System.DebugLog("Original XML extracted from base64 zip:")
System.DebugLog(origXml)