PHP

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

use Chilkat2\Ftp2;

$ftp = new Ftp2();

$ftp->Hostname = 'ftp.example.com';
$ftp->Username = 'myFtpLogin';

$ftp->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->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->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->TlsPinSet = 'sha256//YLh1dUR9y6Kja30RrAn7JKnbQG/uEtLMkBgFF2Fuihg=';

try {
    $ftp->Connect();
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}

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

try {
    $ftp->Disconnect();
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}