(PHP Extension) XML Signature Multiple External References

Demonstrates how to add multiple external references to an XML digital signature.

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<?php

include("chilkat.php");
// Use "chilkat_9_5_0.php" for versions of Chilkat < 10.0.0

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

// This example creates the following signed XML with multiple external references:

// <?xml version="1.0" encoding="UTF-8"?>
// <ds:Signature xmlns:ds="http://www.w3.org/2000/09/xmldsig#" Id="xmldsig-2dde88a8-def0-43e4-8570-b031015a46b4">
//     <ds:SignedInfo>
//         <ds:CanonicalizationMethod Algorithm="http://www.w3.org/TR/2001/REC-xml-c14n-20010315"/>
//         <ds:SignatureMethod Algorithm="http://www.w3.org/2001/04/xmldsig-more#rsa-sha256"/>
//         <ds:Reference Id="xmldsig-2dde88a8-def0-43e4-8570-b031015a46b4-ref0" URI="https://isus.ezdrowie.gov.pl/fhir/Patient/123/_history/456">
//             <ds:DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256"/>
//             <ds:DigestValue>...</ds:DigestValue>
//         </ds:Reference>
//         <ds:Reference Id="xmldsig-2dde88a8-def0-43e4-8570-b031015a46b4-ref1" URI="https://isus.ezdrowie.gov.pl/fhir/Encounter/124/_history/22">
//             <ds:DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256"/>
//             <ds:DigestValue>...</ds:DigestValue>
//         </ds:Reference>
//         <ds:Reference Id="xmldsig-2dde88a8-def0-43e4-8570-b031015a46b4-ref2" URI="https://isus.ezdrowie.gov.pl/fhir/Condition/125/_history/1">
//             <ds:DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256"/>
//             <ds:DigestValue>...</ds:DigestValue>
//         </ds:Reference>
//         <ds:Reference Id="xmldsig-2dde88a8-def0-43e4-8570-b031015a46b4-ref3" URI="https://isus.ezdrowie.gov.pl/fhir/Procedure/126/_history/1">
//             <ds:DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256"/>
//             <ds:DigestValue>...</ds:DigestValue>
//         </ds:Reference>
//         <ds:Reference Type="http://uri.etsi.org/01903#SignedProperties" URI="#xmldsig-2dde88a8-def0-43e4-8570-b031015a46b4-signedprops">
//             <ds:Transforms>
//                 <ds:Transform Algorithm="http://www.w3.org/TR/2001/REC-xml-c14n-20010315"/>
//             </ds:Transforms>
//             <ds:DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256"/>
//             <ds:DigestValue>...</ds:DigestValue>
//         </ds:Reference>
//     </ds:SignedInfo>
//     <ds:SignatureValue Id="xmldsig-2dde88a8-def0-43e4-8570-b031015a46b4-sigvalue">...</ds:SignatureValue>
//     <ds:KeyInfo>
//         <ds:X509Data>
//             <ds:X509Certificate>...</ds:X509Certificate>
//             <ds:X509SubjectName>...</ds:X509SubjectName>
//             <ds:X509IssuerSerial>
//                 <ds:X509IssuerName>...</ds:X509IssuerName>
//                 <ds:X509SerialNumber>...</ds:X509SerialNumber>
//             </ds:X509IssuerSerial>
//         </ds:X509Data>
//     </ds:KeyInfo>
//     <ds:Object>
//         <xades:QualifyingProperties xmlns:xades="http://uri.etsi.org/01903/v1.3.2#" xmlns:xades141="http://uri.etsi.org/01903/v1.4.1#" Target="#xmldsig-2dde88a8-def0-43e4-8570-b031015a46b4">
//             <xades:SignedProperties Id="xmldsig-2dde88a8-def0-43e4-8570-b031015a46b4-signedprops">
//                 <xades:SignedSignatureProperties>
//                     <xades:SigningTime>2021-06-02T07:10:13.306+02:00</xades:SigningTime>
//                     <xades:SigningCertificate>
//                         <xades:Cert>
//                             <xades:CertDigest>
//                                 <ds:DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256"/>
//                                 <ds:DigestValue>...</ds:DigestValue>
//                             </xades:CertDigest>
//                             <xades:IssuerSerial>
//                                 <ds:X509IssuerName>...</ds:X509IssuerName>
//                                 <ds:X509SerialNumber>...</ds:X509SerialNumber>
//                             </xades:IssuerSerial>
//                         </xades:Cert>
//                         <xades:Cert>
//                             <xades:CertDigest>
//                                 <ds:DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256"/>
//                                 <ds:DigestValue>...</ds:DigestValue>
//                             </xades:CertDigest>
//                             <xades:IssuerSerial>
//                                 <ds:X509IssuerName>...</ds:X509IssuerName>
//                                 <ds:X509SerialNumber>...</ds:X509SerialNumber>
//                             </xades:IssuerSerial>
//                         </xades:Cert>
//                         <xades:Cert>
//                             <xades:CertDigest>
//                                 <ds:DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256"/>
//                                 <ds:DigestValue>...</ds:DigestValue>
//                             </xades:CertDigest>
//                             <xades:IssuerSerial>
//                                 <ds:X509IssuerName>...</ds:X509IssuerName>
//                                 <ds:X509SerialNumber>...</ds:X509SerialNumber>
//                             </xades:IssuerSerial>
//                         </xades:Cert>
//                     </xades:SigningCertificate>
//                 </xades:SignedSignatureProperties>
//             </xades:SignedProperties>
//         </xades:QualifyingProperties>
//     </ds:Object>
// </ds:Signature>
// 

$success = true;
$gen = new CkXmlDSigGen();

$gen->put_SigLocation('');
$gen->put_SigLocationMod(0);
// Note: ID's simply need to be unique values in the signed XML document.  They don't necessarily need to be GUID/UUID formatted.
$gen->put_SigId('xmldsig-2dde88a8-def0-43e4-8570-b031015a46b4');
$gen->put_SigNamespacePrefix('ds');
$gen->put_SigNamespaceUri('http://www.w3.org/2000/09/xmldsig#');
$gen->put_SigValueId('xmldsig-2dde88a8-def0-43e4-8570-b031015a46b4-sigvalue');
$gen->put_SignedInfoCanonAlg('C14N');
$gen->put_SignedInfoDigestMethod('sha256');

// 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('xmlns:xades141','http://uri.etsi.org/01903/v1.4.1#');
$object1->AddAttribute('Target','#xmldsig-2dde88a8-def0-43e4-8570-b031015a46b4');
$object1->UpdateAttrAt('xades:SignedProperties',true,'Id','xmldsig-2dde88a8-def0-43e4-8570-b031015a46b4-signedprops');
$object1->UpdateChildContent('xades:SignedProperties|xades:SignedSignatureProperties|xades:SigningTime','TO BE GENERATED BY CHILKAT');
// This assumes there are 3 certs in the certificate chain:  The signing certificate, an intermediate root, and the root CA.
// Remove the lines with "Cert[2]" if there is no intermediate root...
$object1->UpdateAttrAt('xades:SignedProperties|xades:SignedSignatureProperties|xades:SigningCertificateV2|xades:Cert|xades:CertDigest|ds:DigestMethod',true,'Algorithm','http://www.w3.org/2001/04/xmlenc#sha256');
$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');

$gen->AddObject('',$object1->getXml(),'','');

$http = new CkHttp();
$bd = new CkBinData();

$url = 'https://isus.ezdrowie.gov.pl/fhir/Patient/123/_history/456';
$success = $http->QuickGetBd($url,$bd);
if ($success != true) {
    print $http->lastErrorText() . "\n";
    exit;
}

// -------- Reference 1 --------
$gen->AddExternalBinaryRef($url,$bd,'sha256','');
$gen->SetRefIdAttr($url,'xmldsig-2dde88a8-def0-43e4-8570-b031015a46b4-ref0');

// -------- Reference 2 --------
$bd->Clear();
$url = 'https://isus.ezdrowie.gov.pl/fhir/Encounter/789/_history/1';
$success = $http->QuickGetBd($url,$bd);
if ($success != true) {
    print $http->lastErrorText() . "\n";
    exit;
}

$gen->AddExternalBinaryRef($url,$bd,'sha256','');
$gen->SetRefIdAttr($url,'xmldsig-2dde88a8-def0-43e4-8570-b031015a46b4-ref1');

// -------- Reference 3 --------
$bd->Clear();
$url = 'https://isus.ezdrowie.gov.pl/fhir/Condition/123456/_history/1';
$success = $http->QuickGetBd($url,$bd);
if ($success != true) {
    print $http->lastErrorText() . "\n";
    exit;
}

$gen->AddExternalBinaryRef($url,$bd,'sha256','');
$gen->SetRefIdAttr($url,'xmldsig-2dde88a8-def0-43e4-8570-b031015a46b4-ref2');

// -------- Reference 4 --------
$bd->Clear();
$url = 'https://isus.ezdrowie.gov.pl/fhir/Procedure/123456/_history/1';
$success = $http->QuickGetBd($url,$bd);
if ($success != true) {
    print $http->lastErrorText() . "\n";
    exit;
}

$gen->AddExternalBinaryRef($url,$bd,'sha256','');
$gen->SetRefIdAttr($url,'xmldsig-2dde88a8-def0-43e4-8570-b031015a46b4-ref3');

// -------- Reference 5 --------
$gen->AddObjectRef('xmldsig-2dde88a8-def0-43e4-8570-b031015a46b4-signedprops','sha256','C14N','','http://uri.etsi.org/01903#SignedProperties');

// 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('IssuerSerial,SubjectName,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();

$gen->put_Behaviors('IndentedSignature');

// 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";

?>