Perl

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.

Chilkat Perl Downloads

Download Chilkat for Perl

Perl

use chilkat();

$success = 0;

$ftp = chilkat::CkFtp2->new();

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

$ftp->put_AuthTls(1);

#  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 0, which does not reject on verification
#  failure -- set 1 for security.
$ftp->put_RequireSslCertVerify(1);

#  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 == 0) {
    print $ftp->lastErrorText() . "\r\n";
    exit;
}

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

$success = $ftp->Disconnect();
if ($success == 0) {
    print $ftp->lastErrorText() . "\r\n";
    exit;
}