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B4X Requires Chilkat v11.0.0+

Signed Zip as Base64 with XAdES-BES

See more XAdES Examples

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 = 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 ChilkatStringBuilder
sbXmlToZip.Initialize
success = sbXmlToZip.LoadFile("qa_data/xml/PIT-11Z.xml", "utf-8")
If success <> True Then
    Log("Failed to load the XML to be zipped.")
    Return
End If


Dim zip As ChilkatZip
zip.Initialize("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.
zip.AddSb("PIT-11Z.xml", sbXmlToZip, "utf-8")

'  Write the zip to a BinData object.
Dim bdZip As ChilkatBinData
bdZip.Initialize
zip.WriteBd(bdZip)
'  The contents of the bdZip will be retrieved in base64 format when needed below..

Dim gen As ChilkatXmlDSigGen
gen.Initialize("gen")

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 ChilkatXml
object1.Initialize
object1.Tag = "xades:QualifyingProperties"
object1.AddAttribute("xmlns:xades", "http://uri.etsi.org/01903/v1.3.2#")
object1.AddAttribute("Id", "QualifyingProperties_2a8df7f8-b958-40cc-83f6-edb53b837347_43")
object1.AddAttribute("Target", "#Signature_2a8df7f8-b958-40cc-83f6-edb53b837347_19")
object1.UpdateAttrAt("xades:SignedProperties", True, "Id", "SignedProperties_2a8df7f8-b958-40cc-83f6-edb53b837347_4e")
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
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")
object1.UpdateAttrAt("xades:SignedProperties|xades:SignedDataObjectProperties", True, "Id", "SignedDataObjectProperties_2a8df7f8-b958-40cc-83f6-edb53b837347_4b")
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" & Chr(13) & Chr(10) & "Content-Type: application/zip" & Chr(13) & Chr(10) & "Content-Transfer-Encoding: binary" & Chr(13) & Chr(10) & "Content-Disposition: filename=&quot;PIT-11Z.zip&quot;")
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", "")
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
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
gen.AddObject("Object1_2a8df7f8-b958-40cc-83f6-edb53b837347", bdZip.GetEncoded("base64"), "", "http://www.w3.org/2000/09/xmldsig#base64")

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

'  -------- Reference 2 --------
gen.AddObjectRef("SignedProperties_2a8df7f8-b958-40cc-83f6-edb53b837347_4e", "sha1", "", "", "http://uri.etsi.org/01903#SignedProperties")
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 ChilkatCert
cert.Initialize("cert")
success = cert.LoadPfxFile("qa_data/pfx/cert_test123.pfx", "test123")
If success = False Then
    Log(cert.LastErrorText)
    Return
End If


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 ChilkatStringBuilder
sbXml.Initialize

'  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
    Log(gen.LastErrorText)
    Return
End If


'  -----------------------------------------------

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

Log(sbXml.GetAsString)

'  ----------------------------------------
'  Verify the signature we just produced...
Dim verifier As ChilkatXmlDSig
verifier.Initialize
success = verifier.LoadSignatureSb(sbXml)
If success = False Then
    Log(verifier.LastErrorText)
    Return
End If


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

Log("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 ChilkatXml
xml.Initialize
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 = xml.GetChildContent("ds:Object[1]")

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


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


'  Get the 1st file in the zip, which should be the PIT-11Z.xml
Dim entry As ChilkatZipEntry
entry.Initialize("entry")
success = zip.EntryAt(0, entry)
If success = False Then
    Log("Zip contains no files...")
    Return
End If


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