(C) 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

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#include <C_CkStringBuilder.h>
#include <C_CkZip.h>
#include <C_CkZipEntry.h>
#include <C_CkBinData.h>
#include <C_CkXmlDSigGen.h>
#include <C_CkXml.h>
#include <C_CkCert.h>
#include <C_CkXmlDSig.h>

void ChilkatSample(void)
    {
    HCkStringBuilder sbXmlToZip;
    BOOL success;
    HCkZip zip;
    HCkZipEntry entry;
    HCkBinData bdZip;
    HCkXmlDSigGen gen;
    HCkXml object1;
    HCkCert cert;
    HCkStringBuilder sbXml;
    HCkXmlDSig verifier;
    BOOL verified;
    HCkXml xml;
    const char *strZipBase64;
    const char *origXml;

    // 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 = CkStringBuilder_Create();
    success = CkStringBuilder_LoadFile(sbXmlToZip,"qa_data/xml/PIT-11Z.xml","utf-8");
    if (success != TRUE) {
        printf("Failed to load the XML to be zipped.\n");
        CkStringBuilder_Dispose(sbXmlToZip);
        return;
    }

    zip = CkZip_Create();

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

    // Add the XML to be zipped.
    entry = CkZip_AppendString(zip,"PIT-11Z.xml",CkStringBuilder_getAsString(sbXmlToZip));
    CkZipEntry_Dispose(entry);

    // Write the zip to a BinData object.
    bdZip = CkBinData_Create();
    CkZip_WriteBd(zip,bdZip);
    // The contents of the bdZip will be retrieved in base64 format when needed below..

    gen = CkXmlDSigGen_Create();

    CkXmlDSigGen_putSigLocation(gen,"");
    CkXmlDSigGen_putSigLocationMod(gen,0);

    CkXmlDSigGen_putSigId(gen,"Signature_2a8df7f8-b958-40cc-83f6-edb53b837347_19");
    CkXmlDSigGen_putSigNamespacePrefix(gen,"ds");
    CkXmlDSigGen_putSigNamespaceUri(gen,"http://www.w3.org/2000/09/xmldsig#");
    CkXmlDSigGen_putSigValueId(gen,"SignatureValue_2a8df7f8-b958-40cc-83f6-edb53b837347_52");
    CkXmlDSigGen_putSignedInfoId(gen,"SignedInfo_2a8df7f8-b958-40cc-83f6-edb53b837347_41");
    CkXmlDSigGen_putSignedInfoCanonAlg(gen,"C14N");
    CkXmlDSigGen_putSignedInfoDigestMethod(gen,"sha1");

    // Set the KeyInfoId before adding references..
    CkXmlDSigGen_putKeyInfoId(gen,"KeyInfo_2a8df7f8-b958-40cc-83f6-edb53b837347_24");

    // Create an Object to be added to the Signature.
    object1 = CkXml_Create();
    CkXml_putTag(object1,"xades:QualifyingProperties");
    CkXml_AddAttribute(object1,"xmlns:xades","http://uri.etsi.org/01903/v1.3.2#");
    CkXml_AddAttribute(object1,"Id","QualifyingProperties_2a8df7f8-b958-40cc-83f6-edb53b837347_43");
    CkXml_AddAttribute(object1,"Target","#Signature_2a8df7f8-b958-40cc-83f6-edb53b837347_19");
    CkXml_UpdateAttrAt(object1,"xades:SignedProperties",TRUE,"Id","SignedProperties_2a8df7f8-b958-40cc-83f6-edb53b837347_4e");
    CkXml_UpdateAttrAt(object1,"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.
    CkXml_UpdateChildContent(object1,"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
    CkXml_UpdateAttrAt(object1,"xades:SignedProperties|xades:SignedSignatureProperties|xades:SigningCertificate|xades:Cert|xades:CertDigest|ds:DigestMethod",TRUE,"Algorithm","http://www.w3.org/2000/09/xmldsig#sha1");
    CkXml_UpdateChildContent(object1,"xades:SignedProperties|xades:SignedSignatureProperties|xades:SigningCertificate|xades:Cert|xades:CertDigest|ds:DigestValue","TO BE GENERATED BY CHILKAT");
    CkXml_UpdateChildContent(object1,"xades:SignedProperties|xades:SignedSignatureProperties|xades:SigningCertificate|xades:Cert|xades:IssuerSerial|ds:X509IssuerName","TO BE GENERATED BY CHILKAT");
    CkXml_UpdateChildContent(object1,"xades:SignedProperties|xades:SignedSignatureProperties|xades:SigningCertificate|xades:Cert|xades:IssuerSerial|ds:X509SerialNumber","TO BE GENERATED BY CHILKAT");
    CkXml_UpdateAttrAt(object1,"xades:SignedProperties|xades:SignedDataObjectProperties",TRUE,"Id","SignedDataObjectProperties_2a8df7f8-b958-40cc-83f6-edb53b837347_4b");
    CkXml_UpdateAttrAt(object1,"xades:SignedProperties|xades:SignedDataObjectProperties|xades:DataObjectFormat",TRUE,"ObjectReference","#Reference1_2a8df7f8-b958-40cc-83f6-edb53b837347_27");
    CkXml_UpdateChildContent(object1,"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;");
    CkXml_UpdateAttrAt(object1,"xades:SignedProperties|xades:SignedDataObjectProperties|xades:DataObjectFormat|xades:ObjectIdentifier|xades:Identifier",TRUE,"Qualifier","OIDAsURI");
    CkXml_UpdateChildContent(object1,"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");
    CkXml_UpdateChildContent(object1,"xades:SignedProperties|xades:SignedDataObjectProperties|xades:DataObjectFormat|xades:ObjectIdentifier|xades:Description","Opis formatu dokumentu oraz jego pelna nazwa");
    CkXml_UpdateChildContent(object1,"xades:SignedProperties|xades:SignedDataObjectProperties|xades:DataObjectFormat|xades:ObjectIdentifier|xades:DocumentationReferences|xades:DocumentationReference","http://www.certum.pl/OIDAsURI/signedFile.pdf");
    CkXml_UpdateChildContent(object1,"xades:SignedProperties|xades:SignedDataObjectProperties|xades:DataObjectFormat|xades:MimeType","application/zip");
    CkXml_UpdateChildContent(object1,"xades:SignedProperties|xades:SignedDataObjectProperties|xades:CommitmentTypeIndication|xades:CommitmentTypeId|xades:Identifier","http://uri.etsi.org/01903/v1.2.2#ProofOfApproval");
    CkXml_UpdateChildContent(object1,"xades:SignedProperties|xades:SignedDataObjectProperties|xades:CommitmentTypeIndication|xades:AllSignedDataObjects","");
    CkXml_UpdateAttrAt(object1,"xades:UnsignedProperties",TRUE,"Id","UnsignedProperties_2a8df7f8-b958-40cc-83f6-edb53b837347_55");

    // Emit XML in compact (single-line) format to avoid whitespace problems.
    CkXml_putEmitCompact(object1,TRUE);
    CkXmlDSigGen_AddObject(gen,"",CkXml_getXml(object1),"","");

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

    // -------- Reference 1 --------
    CkXmlDSigGen_AddObjectRef(gen,"Object1_2a8df7f8-b958-40cc-83f6-edb53b837347","sha1","C14N_WithComments","","");
    CkXmlDSigGen_SetRefIdAttr(gen,"Object1_2a8df7f8-b958-40cc-83f6-edb53b837347","Reference1_2a8df7f8-b958-40cc-83f6-edb53b837347_27");

    // -------- Reference 2 --------
    CkXmlDSigGen_AddObjectRef(gen,"SignedProperties_2a8df7f8-b958-40cc-83f6-edb53b837347_4e","sha1","","","http://uri.etsi.org/01903#SignedProperties");
    CkXmlDSigGen_SetRefIdAttr(gen,"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 = CkCert_Create();
    success = CkCert_LoadPfxFile(cert,"qa_data/pfx/cert_test123.pfx","test123");
    if (success != TRUE) {
        printf("%s\n",CkCert_lastErrorText(cert));
        CkStringBuilder_Dispose(sbXmlToZip);
        CkZip_Dispose(zip);
        CkBinData_Dispose(bdZip);
        CkXmlDSigGen_Dispose(gen);
        CkXml_Dispose(object1);
        CkCert_Dispose(cert);
        return;
    }

    CkXmlDSigGen_SetX509Cert(gen,cert,TRUE);

    CkXmlDSigGen_putKeyInfoType(gen,"X509Data");
    CkXmlDSigGen_putX509Type(gen,"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 = CkStringBuilder_Create();

    // 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.)
    CkXmlDSigGen_putBehaviors(gen,"AttributeSortingBug,CompactSignedXml");

    // Sign the XML...
    success = CkXmlDSigGen_CreateXmlDSigSb(gen,sbXml);
    if (success != TRUE) {
        printf("%s\n",CkXmlDSigGen_lastErrorText(gen));
        CkStringBuilder_Dispose(sbXmlToZip);
        CkZip_Dispose(zip);
        CkBinData_Dispose(bdZip);
        CkXmlDSigGen_Dispose(gen);
        CkXml_Dispose(object1);
        CkCert_Dispose(cert);
        CkStringBuilder_Dispose(sbXml);
        return;
    }

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

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

    printf("%s\n",CkStringBuilder_getAsString(sbXml));

    // ----------------------------------------
    // Verify the signature we just produced...
    verifier = CkXmlDSig_Create();
    success = CkXmlDSig_LoadSignatureSb(verifier,sbXml);
    if (success != TRUE) {
        printf("%s\n",CkXmlDSig_lastErrorText(verifier));
        CkStringBuilder_Dispose(sbXmlToZip);
        CkZip_Dispose(zip);
        CkBinData_Dispose(bdZip);
        CkXmlDSigGen_Dispose(gen);
        CkXml_Dispose(object1);
        CkCert_Dispose(cert);
        CkStringBuilder_Dispose(sbXml);
        CkXmlDSig_Dispose(verifier);
        return;
    }

    verified = CkXmlDSig_VerifySignature(verifier,TRUE);
    if (verified != TRUE) {
        printf("%s\n",CkXmlDSig_lastErrorText(verifier));
        CkStringBuilder_Dispose(sbXmlToZip);
        CkZip_Dispose(zip);
        CkBinData_Dispose(bdZip);
        CkXmlDSigGen_Dispose(gen);
        CkXml_Dispose(object1);
        CkCert_Dispose(cert);
        CkStringBuilder_Dispose(sbXml);
        CkXmlDSig_Dispose(verifier);
        return;
    }

    printf("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 = CkXml_Create();
    CkXml_LoadSb(xml,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 = CkXml_getChildContent(xml,"ds:Object[1]");

    CkBinData_Clear(bdZip);
    CkBinData_AppendEncoded(bdZip,strZipBase64,"base64");
    if (CkBinData_getNumBytes(bdZip) == 0) {
        printf("Something went wrong.. we dont' have any data..\n");
        CkStringBuilder_Dispose(sbXmlToZip);
        CkZip_Dispose(zip);
        CkBinData_Dispose(bdZip);
        CkXmlDSigGen_Dispose(gen);
        CkXml_Dispose(object1);
        CkCert_Dispose(cert);
        CkStringBuilder_Dispose(sbXml);
        CkXmlDSig_Dispose(verifier);
        CkXml_Dispose(xml);
        return;
    }

    success = CkZip_OpenBd(zip,bdZip);
    if (success != TRUE) {
        printf("%s\n",CkZip_lastErrorText(zip));
        CkStringBuilder_Dispose(sbXmlToZip);
        CkZip_Dispose(zip);
        CkBinData_Dispose(bdZip);
        CkXmlDSigGen_Dispose(gen);
        CkXml_Dispose(object1);
        CkCert_Dispose(cert);
        CkStringBuilder_Dispose(sbXml);
        CkXmlDSig_Dispose(verifier);
        CkXml_Dispose(xml);
        return;
    }

    // Get the 1st file in the zip, which should be the PIT-11Z.xml
    entry = CkZip_GetEntryByIndex(zip,0);
    if (CkZip_getLastMethodSuccess(zip) != TRUE) {
        printf("Zip contains no files...\n");
        CkStringBuilder_Dispose(sbXmlToZip);
        CkZip_Dispose(zip);
        CkBinData_Dispose(bdZip);
        CkXmlDSigGen_Dispose(gen);
        CkXml_Dispose(object1);
        CkCert_Dispose(cert);
        CkStringBuilder_Dispose(sbXml);
        CkXmlDSig_Dispose(verifier);
        CkXml_Dispose(xml);
        return;
    }

    // Get the XML:
    origXml = CkZipEntry_unzipToString(entry,0,"utf-8");
    printf("Original XML extracted from base64 zip:\n");
    printf("%s\n",origXml);

    CkZipEntry_Dispose(entry);


    CkStringBuilder_Dispose(sbXmlToZip);
    CkZip_Dispose(zip);
    CkBinData_Dispose(bdZip);
    CkXmlDSigGen_Dispose(gen);
    CkXml_Dispose(object1);
    CkCert_Dispose(cert);
    CkStringBuilder_Dispose(sbXml);
    CkXmlDSig_Dispose(verifier);
    CkXml_Dispose(xml);

    }