Ruby

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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Ruby

require 'chilkat'

success = false

ftp = Chilkat::CkFtp2.new()

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
end

#  SslServerCertVerified reports whether the certificate chain was successfully verified.
if (ftp.get_SslServerCertVerified())
    print "The server certificate was verified." + "\n";
end

success = ftp.Disconnect()
if (success == false)
    print ftp.lastErrorText() + "\n";
    exit
end