(PHP Extension) Export a Certificate's Private Key to Various Formats

Loads a digital certificate and private key from a PFX file (also known as PKCS#12) and exports the private key to various formats: (1) PKCS8 Encrypted, (2) PKCS8 Encrypted PEM, (3) PKCS8 unencrypted, (4) PKCS8 PEM unencrypted, (5) RSA DER unencrypted, (6) RSA PEM unencrypted, (7) XML.

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");

$cert = new CkCert();

// Load from the PFX file
$pfxFilename = '/Users/chilkat/testData/pfx/chilkat_ssl_pwd_is_test.pfx';
$pfxPassword = 'test';

// A PFX typically contains certificates in the chain of authentication.
// The Chilkat cert object will choose the certificate w/
// private key farthest from the root authority cert.
// To access all the certificates in a PFX, use the 
// Chilkat certificate store object instead.
$success = $cert->LoadPfxFile($pfxFilename,$pfxPassword);
if ($success != true) {
    print $cert->lastErrorText() . "\n";
    exit;
}

// Get the private key...

// privKey is a CkPrivateKey
$privKey = $cert->ExportPrivateKey();
if ($cert->get_LastMethodSuccess() == false) {
    print $cert->lastErrorText() . "\n";
    exit;
}

// Export to various formats:

$password = 'secret';

// PKCS8 Encrypted DER
$path = '/Users/chilkat/testData/privkeys/chilkat_pkcs8_enc.der';
$success = $privKey->SavePkcs8EncryptedFile($password,$path);
if ($success != true) {
    print $privKey->lastErrorText() . "\n";

    exit;
}

// PKCS8 Encrypted PEM
$path = '/Users/chilkat/testData/privkeys/chilkat_pkcs8_enc.pem';
$success = $privKey->SavePkcs8EncryptedPemFile($password,$path);
if ($success != true) {
    print $privKey->lastErrorText() . "\n";

    exit;
}

// PKCS8 Unencrypted DER
$path = '/Users/chilkat/testData/privkeys/chilkat_pkcs8.der';
$success = $privKey->SavePkcs8File($path);
if ($success != true) {
    print $privKey->lastErrorText() . "\n";

    exit;
}

// PKCS8 Unencrypted PEM
$path = '/Users/chilkat/testData/privkeys/chilkat_pkcs8.pem';
$success = $privKey->SavePkcs8PemFile($path);
if ($success != true) {
    print $privKey->lastErrorText() . "\n";

    exit;
}

//  RSA DER (unencrypted)
$path = '/Users/chilkat/testData/privkeys/chilkat_rsa.der';
$success = $privKey->SavePkcs1File($path);
if ($success != true) {
    print $privKey->lastErrorText() . "\n";

    exit;
}

// RSA PEM (unencrypted)
$path = '/Users/chilkat/testData/privkeys/chilkat_rsa.pem';
$success = $privKey->SavePemFile($path);
if ($success != true) {
    print $privKey->lastErrorText() . "\n";

    exit;
}

// XML (unencrypted)
$path = '/Users/chilkat/testData/privkeys/chilkat.xml';
$success = $privKey->SaveXmlFile($path);
if ($success != true) {
    print $privKey->lastErrorText() . "\n";

    exit;
}

print 'Private key exported to all formats.' . "\n";

?>