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Require Specific FTPS Server Certificate Fields

Demonstrates the Chilkat Ftp2.SetSslCertRequirement method, which adds a required match against the FTP server certificate. The first argument selects the certificate field (such as SubjectCN or IssuerCN) and the second is the required value. It is a void method; a non-matching certificate causes the connection to fail.

Background: Standard TLS validation confirms a certificate is trusted and valid for the hostname, but it does not guarantee you reached the specific server you expect — a form of pinning closes that gap. Requiring a certificate field to match a known value rejects any certificate that does not, defending against a mis-issued or substituted certificate even if it would otherwise pass validation. Multiple requirements can be added, and all must be satisfied.

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Local $bSuccess = False

;  Demonstrates the Ftp2.SetSslCertRequirement method, which adds a required match against the FTP
;  server certificate.  The 1st argument selects the certificate field and the 2nd is the required
;  value.  It is a void method.

$oFtp = ObjCreate("Chilkat.Ftp2")

$oFtp.Hostname = "ftp.example.com"
$oFtp.Username = "myFtpLogin"

;  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.
$oFtp.Password = "myPassword"

;  Use explicit FTPS (AUTH TLS) on the standard FTP port.
$oFtp.AuthTls = True

;  Require that the server certificate's subject common name matches an expected value.  If the
;  presented certificate does not match, the TLS connection fails.  Supported fields include
;  SubjectDN, SubjectCN, IssuerDN, IssuerCN, and others.
$oFtp.SetSslCertRequirement "SubjectCN","ftp.example.com"

$bSuccess = $oFtp.Connect()
If ($bSuccess = False) Then
    ConsoleWrite($oFtp.LastErrorText & @CRLF)
    Exit
EndIf

ConsoleWrite("Connected; server certificate met the requirement." & @CRLF)

$bSuccess = $oFtp.Disconnect()
If ($bSuccess = False) Then
    ConsoleWrite($oFtp.LastErrorText & @CRLF)
    Exit
EndIf