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Visual FoxPro

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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LOCAL lnSuccess
LOCAL loSbXmlToZip
LOCAL loZip
LOCAL loBdZip
LOCAL loGen
LOCAL loObject1
LOCAL loCert
LOCAL loSbXml
LOCAL loVerifier
LOCAL lnVerified
LOCAL loXml
LOCAL lcStrZipBase64
LOCAL loEntry
LOCAL lcOrigXml

lnSuccess = 0

* 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).
loSbXmlToZip = CreateObject('Chilkat.StringBuilder')
lnSuccess = loSbXmlToZip.LoadFile("qa_data/xml/PIT-11Z.xml","utf-8")
IF (lnSuccess <> 1) THEN
    ? "Failed to load the XML to be zipped."
    RELEASE loSbXmlToZip
    CANCEL
ENDIF

loZip = CreateObject('Chilkat.Zip')

* Initialize the zip object. No file is created in this call.
* It should always return 1.
lnSuccess = loZip.NewZip("PIT-11Z.zip")

* Add the XML to be zipped.
loZip.AddSb("PIT-11Z.xml",loSbXmlToZip,"utf-8")

* Write the zip to a BinData object.
loBdZip = CreateObject('Chilkat.BinData')
loZip.WriteBd(loBdZip)
* The contents of the bdZip will be retrieved in base64 format when needed below..

loGen = CreateObject('Chilkat.XmlDSigGen')

loGen.SigLocation = ""
loGen.SigLocationMod = 0

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

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

* Create an Object to be added to the Signature.
loObject1 = CreateObject('Chilkat.Xml')
loObject1.Tag = "xades:QualifyingProperties"
loObject1.AddAttribute("xmlns:xades","http://uri.etsi.org/01903/v1.3.2#")
loObject1.AddAttribute("Id","QualifyingProperties_2a8df7f8-b958-40cc-83f6-edb53b837347_43")
loObject1.AddAttribute("Target","#Signature_2a8df7f8-b958-40cc-83f6-edb53b837347_19")
loObject1.UpdateAttrAt("xades:SignedProperties",1,"Id","SignedProperties_2a8df7f8-b958-40cc-83f6-edb53b837347_4e")
loObject1.UpdateAttrAt("xades:SignedProperties|xades:SignedSignatureProperties",1,"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.
loObject1.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
loObject1.UpdateAttrAt("xades:SignedProperties|xades:SignedSignatureProperties|xades:SigningCertificateV2|xades:Cert|xades:CertDigest|ds:DigestMethod",1,"Algorithm","http://www.w3.org/2000/09/xmldsig#sha1")
loObject1.UpdateChildContent("xades:SignedProperties|xades:SignedSignatureProperties|xades:SigningCertificateV2|xades:Cert|xades:CertDigest|ds:DigestValue","TO BE GENERATED BY CHILKAT")
loObject1.UpdateChildContent("xades:SignedProperties|xades:SignedSignatureProperties|xades:SigningCertificateV2|xades:Cert|xades:IssuerSerialV2","TO BE GENERATED BY CHILKAT")
loObject1.UpdateAttrAt("xades:SignedProperties|xades:SignedDataObjectProperties",1,"Id","SignedDataObjectProperties_2a8df7f8-b958-40cc-83f6-edb53b837347_4b")
loObject1.UpdateAttrAt("xades:SignedProperties|xades:SignedDataObjectProperties|xades:DataObjectFormat",1,"ObjectReference","#Reference1_2a8df7f8-b958-40cc-83f6-edb53b837347_27")
loObject1.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;")
loObject1.UpdateAttrAt("xades:SignedProperties|xades:SignedDataObjectProperties|xades:DataObjectFormat|xades:ObjectIdentifier|xades:Identifier",1,"Qualifier","OIDAsURI")
loObject1.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")
loObject1.UpdateChildContent("xades:SignedProperties|xades:SignedDataObjectProperties|xades:DataObjectFormat|xades:ObjectIdentifier|xades:Description","Opis formatu dokumentu oraz jego pelna nazwa")
loObject1.UpdateChildContent("xades:SignedProperties|xades:SignedDataObjectProperties|xades:DataObjectFormat|xades:ObjectIdentifier|xades:DocumentationReferences|xades:DocumentationReference","http://www.certum.pl/OIDAsURI/signedFile.pdf")
loObject1.UpdateChildContent("xades:SignedProperties|xades:SignedDataObjectProperties|xades:DataObjectFormat|xades:MimeType","application/zip")
loObject1.UpdateChildContent("xades:SignedProperties|xades:SignedDataObjectProperties|xades:CommitmentTypeIndication|xades:CommitmentTypeId|xades:Identifier","http://uri.etsi.org/01903/v1.2.2#ProofOfApproval")
loObject1.UpdateChildContent("xades:SignedProperties|xades:SignedDataObjectProperties|xades:CommitmentTypeIndication|xades:AllSignedDataObjects","")
loObject1.UpdateAttrAt("xades:UnsignedProperties",1,"Id","UnsignedProperties_2a8df7f8-b958-40cc-83f6-edb53b837347_55")

* Emit XML in compact (single-line) format to avoid whitespace problems.
loObject1.EmitCompact = 1
loGen.AddObject("",loObject1.GetXml(),"","")

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

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

* -------- Reference 2 --------
loGen.AddObjectRef("SignedProperties_2a8df7f8-b958-40cc-83f6-edb53b837347_4e","sha1","","","http://uri.etsi.org/01903#SignedProperties")
loGen.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)
loCert = CreateObject('Chilkat.Cert')
lnSuccess = loCert.LoadPfxFile("qa_data/pfx/cert_test123.pfx","test123")
IF (lnSuccess = 0) THEN
    ? loCert.LastErrorText
    RELEASE loSbXmlToZip
    RELEASE loZip
    RELEASE loBdZip
    RELEASE loGen
    RELEASE loObject1
    RELEASE loCert
    CANCEL
ENDIF

loGen.SetX509Cert(loCert,1)

loGen.KeyInfoType = "X509Data"
loGen.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.
loSbXml = CreateObject('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.)
loGen.Behaviors = "AttributeSortingBug,CompactSignedXml"

* Sign the XML...
lnSuccess = loGen.CreateXmlDSigSb(loSbXml)
IF (lnSuccess = 0) THEN
    ? loGen.LastErrorText
    RELEASE loSbXmlToZip
    RELEASE loZip
    RELEASE loBdZip
    RELEASE loGen
    RELEASE loObject1
    RELEASE loCert
    RELEASE loSbXml
    CANCEL
ENDIF

* -----------------------------------------------

* Save the signed XML to a file.
lnSuccess = loSbXml.WriteFile("qa_output/signedXml.xml","utf-8",0)

? loSbXml.GetAsString()

* ----------------------------------------
* Verify the signature we just produced...
loVerifier = CreateObject('Chilkat.XmlDSig')
lnSuccess = loVerifier.LoadSignatureSb(loSbXml)
IF (lnSuccess = 0) THEN
    ? loVerifier.LastErrorText
    RELEASE loSbXmlToZip
    RELEASE loZip
    RELEASE loBdZip
    RELEASE loGen
    RELEASE loObject1
    RELEASE loCert
    RELEASE loSbXml
    RELEASE loVerifier
    CANCEL
ENDIF

lnVerified = loVerifier.VerifySignature(1)
IF (lnVerified <> 1) THEN
    ? loVerifier.LastErrorText
    RELEASE loSbXmlToZip
    RELEASE loZip
    RELEASE loBdZip
    RELEASE loGen
    RELEASE loObject1
    RELEASE loCert
    RELEASE loSbXml
    RELEASE loVerifier
    CANCEL
ENDIF

? "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.
loXml = CreateObject('Chilkat.Xml')
loXml.LoadSb(loSbXml,1)

* 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.)
lcStrZipBase64 = loXml.GetChildContent("ds:Object[1]")

loBdZip.Clear()
loBdZip.AppendEncoded(lcStrZipBase64,"base64")
IF (loBdZip.NumBytes = 0) THEN
    ? "Something went wrong.. we dont' have any data.."
    RELEASE loSbXmlToZip
    RELEASE loZip
    RELEASE loBdZip
    RELEASE loGen
    RELEASE loObject1
    RELEASE loCert
    RELEASE loSbXml
    RELEASE loVerifier
    RELEASE loXml
    CANCEL
ENDIF

lnSuccess = loZip.OpenBd(loBdZip)
IF (lnSuccess = 0) THEN
    ? loZip.LastErrorText
    RELEASE loSbXmlToZip
    RELEASE loZip
    RELEASE loBdZip
    RELEASE loGen
    RELEASE loObject1
    RELEASE loCert
    RELEASE loSbXml
    RELEASE loVerifier
    RELEASE loXml
    CANCEL
ENDIF

* Get the 1st file in the zip, which should be the PIT-11Z.xml
loEntry = CreateObject('Chilkat.ZipEntry')
lnSuccess = loZip.EntryAt(0,loEntry)
IF (lnSuccess = 0) THEN
    ? "Zip contains no files..."
    RELEASE loSbXmlToZip
    RELEASE loZip
    RELEASE loBdZip
    RELEASE loGen
    RELEASE loObject1
    RELEASE loCert
    RELEASE loSbXml
    RELEASE loVerifier
    RELEASE loXml
    RELEASE loEntry
    CANCEL
ENDIF

* Get the XML:
lcOrigXml = loEntry.UnzipToString(0,"utf-8")
? "Original XML extracted from base64 zip:"
? lcOrigXml

RELEASE loSbXmlToZip
RELEASE loZip
RELEASE loBdZip
RELEASE loGen
RELEASE loObject1
RELEASE loCert
RELEASE loSbXml
RELEASE loVerifier
RELEASE loXml
RELEASE loEntry