(PHP Extension) Create XML Digital Signature using Certificate on Smart Card

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Demonstrates how to load a certificate located on a smart card or USB token and then use it for creating an XML digital signature such that the cryptographic signing happens on the smart card.

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<?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.

$scmd = new CkScMinidriver();

// Reader names (smart card readers or USB tokens) can be discovered
// via List Readers or Find Smart Cards
$readerName = 'SCM Microsystems Inc. SCR33x USB Smart Card Reader 0';
$success = $scmd->AcquireContext($readerName);
if ($success == false) {
    print $scmd->lastErrorText() . "\n";
    exit;
}

// If successful, the name of the currently inserted smart card is available:
print 'Card name: ' . $scmd->cardName() . "\n";

// If desired, perform regular PIN authentication with the smartcard.
// For more details about smart card PIN authentication, see the Smart Card PIN Authentication Example
$retval = $scmd->PinAuthenticate('user','000000');
if ($retval != 0) {
    print 'PIN Authentication failed.' . "\n";
}

// You can find a cerficate using any of the following certificate parts:
// "subjectDN" -- The full distinguished name of the cert.
// "subjectDN_withTags" -- Same as above, but in a format that includes the subject part tags, such as the "CN=" in "CN=something"
// "subjectCN" -- The common name part (CN) of the certificate's subject.
// "serial" -- The certificate serial number.
// "serial:issuerCN" -- The certificate serial number + the issuer's common name, delimited with a colon char.
// These are the same certificate parts that can be retrieved by listing certificates on the smart card (or USB token).
// See List Certificates on Smart Card Example
$certPart = 'subjectCN';
$partValue = 'PIVKey E42D60A759D39147A26E0AF2FB1183C5';

// If the certificate is found, it is loaded into the cert object.
$cert = new CkCert();
$success = $scmd->FindCert($certPart,$partValue,$cert);
if ($success == false) {
    print 'Failed to find the certificate.' . "\n";
    $scmd->DeleteContext();
    exit;
}

print 'Successfully loaded the cert object from the smart card / USB token.' . "\n";

// Note: When successful, the cert object is internally linked to the ScMinidriver object's authenticated session.
// The cert object can now be used to sign or do other cryptographic operations that occur on the smart card / USB token.
// If your application calls PinDeauthenticate or DeleteContext, the cert will no longer be able to sign on the smart card
// because the smart card ScMinidriver session will no longer be authenticated or deleted.

// ------------------------------------------------------------------------------------------------------------
// We have the certificate.  Now let's do the XML digital signature..

// Create the following XML to be signed:

// <?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>

$xml = new CkXml();
$xml->put_Tag('SOAP-ENV:Envelope');
$xml->AddAttribute('xmlns:SOAP-ENV','http://schemas.xmlsoap.org/soap/envelope/');
$xml->UpdateAttrAt('SOAP-ENV:Header|wsse:Security',true,'xmlns:wsse','http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd');
$xml->UpdateAttrAt('SOAP-ENV:Header|wsse:Security',true,'SOAP-ENV:mustUnderstand','1');
$xml->UpdateAttrAt('SOAP-ENV:Body',true,'xmlns:SOAP-SEC','http://schemas.xmlsoap.org/soap/security/2000-12');
$xml->UpdateAttrAt('SOAP-ENV:Body',true,'SOAP-SEC:id','Body');
$xml->UpdateAttrAt('SOAP-ENV:Body|z:FooBar',true,'xmlns:z','http://example.com');

// 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 the base64 of the certificate embedded in the KeyInfo.
$gen->put_KeyInfoType('X509Data');
$gen->put_X509Type('Certificate');

// Note: Our certificate was loaded from the smartcard and is internally linked to the authenticated ScMinidriver session.
// The signing will occur on the smart card using the chosen certificate.
$bUsePrivateKey = true;
$success = $gen->SetX509Cert($cert,$bUsePrivateKey);
if ($success != true) {
    print $gen->lastErrorText() . "\n";
    exit;
}

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

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

// ------------------------------------------------------------------------------------------------------------
// Cleanup our ScMinidriver session...

// When finished with operations that required authentication, you may if you wish, deauthenticate the session.
$success = $scmd->PinDeauthenticate('user');
if ($success == false) {
    print $scmd->lastErrorText() . "\n";
}

// Delete the context when finished with the card.
$success = $scmd->DeleteContext();
if ($success == false) {
    print $scmd->lastErrorText() . "\n";
}


?>