(PHP Extension) Export a Private Key from an MS Storage Provider

Demonstrates how to export a private key from a Microsoft Storage Provider.

Note: This example requires Chilkat v9.5.0.83 or greater.

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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 Chilkat v9.5.0.83 or greater.

// We'll export a certificate's private key from the MS storage provider.
// It is assumed the certificate + private key is already installed on the Windows system.
// The export does not remove the key from the Windows storage provider.

// First, let's get a certificate in one of the many ways we can do it.
// (I ran certmgr.msc, opened a certificate, and noted it's thumbprint.)
$cert = new CkCert();
$success = $cert->LoadByThumbprint('ea5a129c1919a52d238ee28d9f3a8f345b768388','hex');
if ($success == false) {
    print $cert->lastErrorText() . "\n";
    exit;
}

print 'Found: ' . $cert->subjectDN() . "\n";

// First export the private key the easy way.
// privKey is a CkPrivateKey
$privKey = $cert->ExportPrivateKey();
if ($cert->get_LastMethodSuccess() == false) {
    print $cert->lastErrorText() . "\n";
    exit;
}

// OK.. we have the private key.  Do whatever we want with it..

// -------------------------------------------------------------
// Now let's export in a more roundabout way by getting information about the 
// storage provider and key name and then we'll export completely independent
// of the certificate.
// 
// Remember: The private key is not contained within the certificate.  An X.509 certificate
// embeds the public key, but the counterpart private key is stored elsewhere, such
// as in a .pfx/.p12, or as in this case, in the Windows "protected store", or perhaps on
// a smartcard or hardware token.  (But a private key stored on a smartcard or token cannot
// be exported.  It must remain on the hardware.)
// 

$storageProvider = $cert->cspName();
$keyName = $cert->keyContainerName();

print 'Information about the certificate's private key:' . "\n";
print 'Storage Provider: ' . $storageProvider . "\n";
print 'Key Name: ' . $keyName . "\n";

// Export using just the name of the storage provider and key.
$keyCon = new CkKeyContainer();
$privKey2 = new CkPrivateKey();
$silentFlag = false;
$success = $keyCon->ExportKey($keyName,$storageProvider,$silentFlag,$privKey2);
if ($success == false) {
    print $keyCon->lastErrorText() . "\n";
    exit;
}

// OK.. we have the private key in privKey2.  Do whatever we want with it..
// Perhaps we save as encrypted PKCS8 PEM.
$success = $privKey2->SavePkcs8EncryptedPemFile('myPassword','qa_output/privKey2.pem');
if ($success == false) {
    print $privKey2->lastErrorText() . "\n";
    exit;
}

print 'Success.' . "\n";

?>