(PHP Extension) Signed Zip as Base64 with XAdES-BES

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

Chilkat PHP Downloads PHP Extension for Windows, Linux, MacOS, Alpine Linux, Solaris

<?php

// The version number (9_5_0) should match version of the Chilkat extension used, omitting the micro-version number.
// For example, if using Chilkat v9.5.0.48, then include as shown here:
include("chilkat_9_5_0.php");

// 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).
$sbXmlToZip = new CkStringBuilder();
$success = $sbXmlToZip->LoadFile('qa_data/xml/PIT-11Z.xml','utf-8');
if ($success != true) {
    print 'Failed to load the XML to be zipped.' . "\n";
    exit;
}

$zip = new CkZip();

// 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.
// entry is a CkZipEntry
$entry = $zip->AppendString('PIT-11Z.xml',$sbXmlToZip->getAsString());

// Write the zip to a BinData object.
$bdZip = new CkBinData();
$zip->WriteBd($bdZip);
// The contents of the bdZip will be retrieved in base64 format when needed below..

$gen = new CkXmlDSigGen();

$gen->put_SigLocation('');
$gen->put_SigLocationMod(0);

$gen->put_SigId('Signature_2a8df7f8-b958-40cc-83f6-edb53b837347_19');
$gen->put_SigNamespacePrefix('ds');
$gen->put_SigNamespaceUri('http://www.w3.org/2000/09/xmldsig#');
$gen->put_SigValueId('SignatureValue_2a8df7f8-b958-40cc-83f6-edb53b837347_52');
$gen->put_SignedInfoId('SignedInfo_2a8df7f8-b958-40cc-83f6-edb53b837347_41');
$gen->put_SignedInfoCanonAlg('C14N');
$gen->put_SignedInfoDigestMethod('sha1');

// Set the KeyInfoId before adding references..
$gen->put_KeyInfoId('KeyInfo_2a8df7f8-b958-40cc-83f6-edb53b837347_24');

// Create an Object to be added to the Signature.
$object1 = new CkXml();
$object1->put_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:SigningCertificate|xades:Cert|xades:CertDigest|ds:DigestMethod',true,'Algorithm','http://www.w3.org/2000/09/xmldsig#sha1');
$object1->UpdateChildContent('xades:SignedProperties|xades:SignedSignatureProperties|xades:SigningCertificate|xades:Cert|xades:CertDigest|ds:DigestValue','TO BE GENERATED BY CHILKAT');
$object1->UpdateChildContent('xades:SignedProperties|xades:SignedSignatureProperties|xades:SigningCertificate|xades:Cert|xades:IssuerSerial|ds:X509IssuerName','TO BE GENERATED BY CHILKAT');
$object1->UpdateChildContent('xades:SignedProperties|xades:SignedSignatureProperties|xades:SigningCertificate|xades:Cert|xades:IssuerSerial|ds:X509SerialNumber','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\r\nContent-Type: application/zip\r\nContent-Transfer-Encoding: binary\r\nContent-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->put_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)
$cert = new CkCert();
$success = $cert->LoadPfxFile('qa_data/pfx/cert_test123.pfx','test123');
if ($success != true) {
    print $cert->lastErrorText() . "\n";
    exit;
}

$gen->SetX509Cert($cert,true);

$gen->put_KeyInfoType('X509Data');
$gen->put_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.
$sbXml = new CkStringBuilder();

// 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->put_Behaviors('AttributeSortingBug,CompactSignedXml');

// Sign the XML...
$success = $gen->CreateXmlDSigSb($sbXml);
if ($success != true) {
    print $gen->lastErrorText() . "\n";
    exit;
}

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

// Save the signed XML to a file.
$success = $sbXml->WriteFile('qa_output/signedXml.xml','utf-8',false);

print $sbXml->getAsString() . "\n";

// ----------------------------------------
// Verify the signature we just produced...
$verifier = new CkXmlDSig();
$success = $verifier->LoadSignatureSb($sbXml);
if ($success != true) {
    print $verifier->lastErrorText() . "\n";
    exit;
}

$verified = $verifier->VerifySignature(true);
if ($verified != true) {
    print $verifier->lastErrorText() . "\n";
    exit;
}

print 'This signature was successfully verified.' . "\n";

// ------------------------------------
// Finally, let's extract the .zip from the signed XML, and then unzip the original PIT-11Z.xml from the in-memory zip.
$xml = new CkXml();
$xml->LoadSb($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.)
$strZipBase64 = $xml->getChildContent('ds:Object[1]');

$bdZip->Clear();
$bdZip->AppendEncoded($strZipBase64,'base64');
if ($bdZip->get_NumBytes() == 0) {
    print 'Something went wrong.. we dont' have any data..' . "\n";
    exit;
}

$success = $zip->OpenBd($bdZip);
if ($success != true) {
    print $zip->lastErrorText() . "\n";
    exit;
}

// Get the 1st file in the zip, which should be the PIT-11Z.xml
// entry is a CkZipEntry
$entry = $zip->GetEntryByIndex(0);
if ($zip->get_LastMethodSuccess() != true) {
    print 'Zip contains no files...' . "\n";
    exit;
}

// Get the XML:
$origXml = $entry->unzipToString(0,'utf-8');
print 'Original XML extracted from base64 zip:' . "\n";
print $origXml . "\n";


?>