(PHP ActiveX) Trust Specific Root CA Certificates

Demonstrates how to trust specific root CA certificates and none others.

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows Note: The php_com_dotnet.dll may need to be enabled inside of php.ini.

<?php

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

// This example will trust the Amazon root CA certificates provided at 
// https://www.amazontrust.com/repository/

// I've previously downloaded the root CA certificates to DER format.
// Add each to the Chilkat TrustedRoots singleton object.

// For versions of Chilkat < 10.0.0, use new COM('Chilkat_9_5_0.Chilkat.TrustedRoots')
$tRoots = new COM("Chilkat.TrustedRoots");

// For versions of Chilkat < 10.0.0, use new COM('Chilkat_9_5_0.Chilkat.Cert')
$caCert = new COM("Chilkat.Cert");
$success = $caCert->LoadFromFile('qa_data/certs/aws_root_ca/AmazonRootCA1.cer');
if ($success == 0) {
    print $caCert->LastErrorText . "\n";
    exit;
}

$success = $tRoots->AddCert($caCert);

// Continue with the others.
// For brevity, we're not checking return values for success/failure.
$success = $caCert->LoadFromFile('qa_data/certs/aws_root_ca/AmazonRootCA2.cer');
$success = $tRoots->AddCert($caCert);

$success = $caCert->LoadFromFile('qa_data/certs/aws_root_ca/AmazonRootCA3.cer');
$success = $tRoots->AddCert($caCert);

$success = $caCert->LoadFromFile('qa_data/certs/aws_root_ca/AmazonRootCA4.cer');
$success = $tRoots->AddCert($caCert);

$success = $caCert->LoadFromFile('qa_data/certs/aws_root_ca/SFSRootCAG2.cer');
$success = $tRoots->AddCert($caCert);

// Indicate we don't want to automatically trust the operating system's installed root CA certificates.
// On a Windows operating system, this would be the registry-based CA certificate stores. 
// On a Linux system, this could be /etc/ssl/certs/ca-certificates.crt, if it exists.
$tRoots->TrustSystemCaRoots = 0;

// Activate the trusted roots object.
// Once activated, all Chilkat objects that use TLS connections (HTTP, REST, Socket, MailMan, IMAP, FTP, etc.)
// will fail the TLS handshake if the server certificate is not verified and rooted with one of our explicitly trusted root certificates.
$success = $tRoots->Activate();

// For versions of Chilkat < 10.0.0, use new COM('Chilkat_9_5_0.Chilkat.Http')
$http = new COM("Chilkat.Http");

// Note: We also need to explicitly indicate that server certificates are to be verified.
$http->RequireSslCertVerify = 1;

// For example, the following should fail because www.chilkatsoft.com's server certificate is not rooted in one of the explicitly trusted root CA certs.
$success = $http->Download('https://www.chilkatsoft.com/helloWorld.txt','qa_output/helloWorld.txt');
if ($success != 1) {
    // The above Download should fail.
    print $http->LastErrorText . "\n";

    // There should be a message in the LastErrorText indicating that we were "Unable to build certificate chain to root.."
}

// However, we should be able to make TLS connections to good.sca1a.amazontrust.com
$success = $http->Download('https://good.sca1a.amazontrust.com/','qa_output/valid.html');
if ($success != 1) {
    print $http->LastErrorText . "\n";
    exit;
}

// We can still examine the LastErrorText and we'll find this message within:  
// "The public key was successfully validated against the public key of the explicitly trusted root cert."
print $http->LastErrorText . "\n";

print 'Success!' . "\n";

?>