(PHP Extension) Create XML Signature with KeyInfo / X509Data / X509SKI

This example demonstrates how to create an XML Digital Signature where the KeyInfo element contains an X509Data element,
which in turn contains an X509SKI element which contains only the signing certificate's Subject Key Identifier.

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

// To begin, we'll need a PFX containing a certificate and private key, and the SOAP XML to be signed.
// Chilkat provides sample data at chilkatsoft.com and chilkatdownload.com, and our first step is to download.

// -------------------------------------------------------------------------
// Step 1: Get the SOAP XML to be signed.
// 
$sbXml = new CkStringBuilder();

$http = new CkHttp();
$success = $http->QuickGetSb('https://www.chilkatsoft.com/exampleData/soapToSign.xml',$sbXml);
if ($success != true) {
    print $http->lastErrorText() . "\n";
    exit;
}

// The SOAP XML contains this:

// <?xml version="1.0" encoding="UTF-8" standalone="no" ?>
// <SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/">
//     <SOAP-ENV:Header>
//         <wsse:Security xmlns:wsse="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd" SOAP-ENV:mustUnderstand="1"></wsse:Security>
//     </SOAP-ENV:Header>
//     <SOAP-ENV:Body xmlns:SOAP-SEC="http://schemas.xmlsoap.org/soap/security/2000-12" SOAP-SEC:id="Body">
//         <z:FooBar xmlns:z="http://example.com" />
//     </SOAP-ENV:Body>
// </SOAP-ENV:Envelope>

// -------------------------------------------------------------------------
// Step 2: Get the test certificate and private key stored in a .pfx
// 
$pfxData = new CkBinData();
$success = $http->QuickGetBd('https://chilkatdownload.com/example_data/testcertificate.pfx',$pfxData);
if ($success != true) {
    print $http->lastErrorText() . "\n";
    exit;
}

$pfx = new CkPfx();
$password = 'test';
$success = $pfx->LoadPfxEncoded($pfxData->getEncoded('base64'),'base64',$password);
if ($success != true) {
    print $pfx->lastErrorText() . "\n";
    exit;
}

// -------------------------------------------------------------------------
// Step 3: Get the certificate from the PFX.
// 
// cert is a CkCert
$cert = $pfx->GetCert(0);
if ($pfx->get_LastMethodSuccess() != true) {
    print $pfx->lastErrorText() . "\n";
    exit;
}

// Prepare for signing...
$gen = new CkXmlDSigGen();

// Indicate where the Signature will be inserted.
$gen->put_SigLocation('SOAP-ENV:Envelope|SOAP-ENV:Header|wsse:Security');

// Add a reference to the fragment of the XML to be signed.

// Note: "Body" refers to the XML element having an "id" equal to "Body", where "id" is case insensitive
// and where any namespace might qualify the attribute.  In this case, the SOAP-ENV:Body fragment is signed
// NOT because the tag = "Body", but because it has SOAP-SEC:id="Body"
$gen->AddSameDocRef('Body','sha1','EXCL_C14N','','');

// (You can read about the SignedInfoPrefixList in the online reference documentation.  It's optional..)
$gen->put_SignedInfoPrefixList('wsse SOAP-ENV');

// Provide the private key for signing via the certificate, and indicate that
// we want only the Subject Key Identifier (SKI) of the certificate embedded in the KeyInfo.
$gen->put_KeyInfoType('X509Data');
$gen->put_X509Type('SKI');

// Note: Because our certificate was loaded from a PFX which also contained the private key,
// Chilkat automatically knows and has the private key associated with the certificate.
// We set bUsePrivateKey to tell the SetX509Cert method to automatically use the private key
// associated with the certificate for signing.  If, for example, we obtained the certificate
// by loading from a .cer file, then we would not already have the associated private key.
// In that case, the application could explicitly load the cert's private key from some
// other source, such as a .key, .pem, etc. and then call gen.SetPrivateKey.
$bUsePrivateKey = true;
$success = $gen->SetX509Cert($cert,$bUsePrivateKey);
if ($success != true) {
    print $gen->lastErrorText() . "\n";

    exit;
}

// Everything's specified.  Now create and insert the Signature
$success = $gen->CreateXmlDSigSb($sbXml);
if ($success != true) {
    print $gen->lastErrorText() . "\n";
    exit;
}

// Examine the XML with the digital signature inserted
print $sbXml->getAsString() . "\n";

// Here is the actual output.  A pretty-printed version of the output is shown below, but the addition of whitespace
// in the XML invalidates the signature.

// <?xml version="1.0" encoding="UTF-8" standalone="no" ?>
// <SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/">
//     <SOAP-ENV:Header>
//         <wsse:Security xmlns:wsse="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd" SOAP-ENV:mustUnderstand="1"><ds:Signature xmlns:ds="http://www.w3.org/2000/09/xmldsig#"><ds:SignedInfo><ds:CanonicalizationMethod Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#"><InclusiveNamespaces xmlns="http://www.w3.org/2001/10/xml-exc-c14n#" PrefixList="wsse SOAP-ENV"/></ds:CanonicalizationMethod><ds:SignatureMethod Algorithm="http://www.w3.org/2001/04/xmldsig-more#rsa-sha256"/><ds:Reference URI="#Body"><ds:Transforms><ds:Transform Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#"/></ds:Transforms><ds:DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1"/><ds:DigestValue>PIiVPpuMc1jGpWaL8ftzTOcc4gc=</ds:DigestValue></ds:Reference></ds:SignedInfo><ds:SignatureValue>Rlta8LplnFH0q8L+UeVmh4Smdn6oVETi4RoUmpT/KQX3RNAIOdCVE3b7gjmx5+3vp3DhjphOsZvW6dXzkI46xt9pD5otp3b/ZppGqKzltggo9gyQtPvJ8ltJZqVKYOGo5uElRFF/xm/zcx5Y3E14t+LYVSlv2lbem/zZ5zQ7ai8DmGD33id7nGu+MXVwb3kGkJFYoB/GOXtwsep+bcilMglTp8/7SBfBaVFKxWVBp4N2NW7bGlyDct8FaCk9hXQDNm/kqne9GU87tgh8/rbsFCYgyqIRMIvMPvhRWr2EKdEKyLtlZ8w0KYJYpgsf4T7SDghemzXkJoJPrfUQmHudIw==</ds:SignatureValue><ds:KeyInfo><ds:X509Data><ds:X509SKI>bDMtm8bAimMlGLU2M/82W8+y3tM=</ds:X509SKI></ds:X509Data></ds:KeyInfo></ds:Signature></wsse:Security>
//     </SOAP-ENV:Header>
//     <SOAP-ENV:Body xmlns:SOAP-SEC="http://schemas.xmlsoap.org/soap/security/2000-12" SOAP-SEC:id="Body">
//         <z:FooBar xmlns:z="http://example.com" />
//     </SOAP-ENV:Body>
// </SOAP-ENV:Envelope>

// ----------------------------------------------------------------
// Pretty-printed output (invalidates the signature)
// This makes it easier to see the X509IssuerSerial contained within the KeyInfo.

// <?xml version="1.0" encoding="UTF-8" standalone="no" ?>
// <SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/">
//     <SOAP-ENV:Header>
//         <wsse:Security xmlns:wsse="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd" SOAP-ENV:mustUnderstand="1">
//             <ds:Signature xmlns:ds="http://www.w3.org/2000/09/xmldsig#">
//                 <ds:SignedInfo>
//                     <ds:CanonicalizationMethod Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#">
//                         <InclusiveNamespaces xmlns="http://www.w3.org/2001/10/xml-exc-c14n#" PrefixList="wsse SOAP-ENV" />
//                     </ds:CanonicalizationMethod>
//                     <ds:SignatureMethod Algorithm="http://www.w3.org/2001/04/xmldsig-more#rsa-sha256" />
//                     <ds:Reference URI="#Body">
//                         <ds:Transforms>
//                             <ds:Transform Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#" />
//                         </ds:Transforms>
//                         <ds:DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1" />
//                         <ds:DigestValue>PIiVPpuMc1jGpWaL8ftzTOcc4gc=</ds:DigestValue>
//                     </ds:Reference>
//                 </ds:SignedInfo>
//                 <ds:SignatureValue>Rlta8LplnFH0q8L+UeVmh4Smdn6oVETi4RoUmpT/KQX3RNAIOdCVE3b7gjmx5+3vp3DhjphOsZvW6dXzkI46xt9pD5otp3b/ZppGqKzltggo9gyQtPvJ8ltJZqVKYOGo5uElRFF/xm/zcx5Y3E14t+LYVSlv2lbem/zZ5zQ7ai8DmGD33id7nGu+MXVwb3kGkJFYoB/GOXtwsep+bcilMglTp8/7SBfBaVFKxWVBp4N2NW7bGlyDct8FaCk9hXQDNm/kqne9GU87tgh8/rbsFCYgyqIRMIvMPvhRWr2EKdEKyLtlZ8w0KYJYpgsf4T7SDghemzXkJoJPrfUQmHudIw==</ds:SignatureValue>
//                 <ds:KeyInfo>
//                     <ds:X509Data>
//                         <ds:X509SKI>bDMtm8bAimMlGLU2M/82W8+y3tM=</ds:X509SKI>
//                     </ds:X509Data>
//                 </ds:KeyInfo>
//             </ds:Signature>
//         </wsse:Security>
//     </SOAP-ENV:Header>
//     <SOAP-ENV:Body xmlns:SOAP-SEC="http://schemas.xmlsoap.org/soap/security/2000-12" SOAP-SEC:id="Body">
//         <z:FooBar xmlns:z="http://example.com" />
//     </SOAP-ENV:Body>
// </SOAP-ENV:Envelope>

?>