(PHP Extension) How to Parse a X.509 Certificate and Extract its Public Key

Demonstrates how to load an X.509 certificate and extract the public key. Chilkat supports many certificate encodings:

• DER (binary) encoded certificates (.crt/.cer)
• PEM (BASE64) encoded certificates (.pem)
• Load Certificates Directly from Windows Certificate Stores
• PFX/PKCS12 (.pfx/.p12)
• Java KeyStore (.jks)
• Cryptographic Message Syntax Standard - PKCS #7 Certificates (.P7B)

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 a DER (binary) encoded certificate.
// To load from a .pem or .p7b, or any other file format that contains
// just one certificate, call LoadFromFile in exactly the same way.
// The LoadFromFile method automatically detects the format and loads the certificate.
$success = $cert->LoadFromFile('qa_data/certs/testCert.cer');
if ($success == false) {
    print $cert->lastErrorText() . "\n";
    exit;
}

// Get the public key:
// pubKey is a CkPublicKey
$pubKey = $cert->ExportPublicKey();
if ($cert->get_LastMethodSuccess() != true) {
    print $cert->lastErrorText() . "\n";
    exit;
}

// Examine the key type.
// A PublicKey object can contain an RSA, ECC, or DSA public key.
// The KeyType property will contain "rsa", "ecc", or "dsa".
print 'key type = ' . $pubKey->keyType() . "\n";


?>