PHP Extension

Verify and Pin the FTPS Server Certificate

Demonstrates the certificate-verification properties RequireSslCertVerify, TlsPinSet, and the read-only SslServerCertVerified.

Background: By default a TLS connection is not rejected merely because certificate-chain verification fails, so RequireSslCertVerify = true is the important hardening step — it makes an expired, unsigned, or untrusted certificate abort the connection. TlsPinSet adds public-key pinning on top: the handshake fails unless the server's SPKI fingerprint matches one you configured, defending against a mis-issued certificate that would otherwise validate. Pinning supplements verification rather than replacing it. SslServerCertVerified reports the outcome.

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PHP Extension

<?php

include("chilkat.php");

$success = false;

$ftp = new CkFtp2();

$ftp->put_Hostname('ftp.example.com');
$ftp->put_Username('myFtpLogin');

$ftp->put_AuthTls(true);

//  Normally you would not hard-code the password in source.  You should instead obtain it
//  from an interactive prompt, environment variable, or a secrets vault.
$ftp->put_Password('myPassword');

//  Reject the connection if the server certificate cannot be verified (expired, bad signature,
//  untrusted chain, etc.).  The default is false, which does not reject on verification
//  failure -- set true for security.
$ftp->put_RequireSslCertVerify(true);

//  Optionally pin the server's public key.  If none of the configured SPKI fingerprints matches,
//  the TLS handshake fails.  Pinning supplements normal verification; it does not replace it.
$ftp->put_TlsPinSet('sha256//YLh1dUR9y6Kja30RrAn7JKnbQG/uEtLMkBgFF2Fuihg=');

$success = $ftp->Connect();
if ($success == false) {
    print $ftp->lastErrorText() . "\n";
    exit;
}

//  SslServerCertVerified reports whether the certificate chain was successfully verified.
if ($ftp->get_SslServerCertVerified()) {
    print 'The server certificate was verified.' . "\n";
}

$success = $ftp->Disconnect();
if ($success == false) {
    print $ftp->lastErrorText() . "\n";
    exit;
}


?>