Verify FTP SSL Server Certificate

This example demonstrates how to verify the FTP server's certificate and authenticity. The intent is to verify the authenticity of the server before passing a login/password to it.

Download Chilkat FTP2 ActiveX

uses
    Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
    Dialogs, StdCtrls,
    CHILKATFTP2Lib_TLB,
    CHILKATCERTIFICATELib_TLB,
    OleCtrls;

...

procedure TForm1.Button1Click(Sender: TObject);
var
ftp: TChilkatFtp2;
success: Integer;
cert: IChilkatCert;

begin
ftp := TChilkatFtp2.Create(Self);

//  Any string unlocks the component for the 1st 30-days.
success := ftp.UnlockComponent('Anything for 30-day trial');
if (success <> 1) then
  begin
    ShowMessage(ftp.LastErrorText);

  end;

ftp.Hostname := 'ftp.myftpserver.com';
ftp.Username := 'myUsername';
ftp.Password := 'myPassword';

//  Establish an AUTH SSL secure channel after connection
//  on the standard FTP port 21.
ftp.AuthSsl := 1;

//  The Ssl property is for establishing an implicit SSL connection
//  on port 990.  Do not set it.
ftp.Ssl := 0;

//  Indicate that the FTP server must have a verifiable SSL certificate.
//  Do not accept self-signed certs or certificates that are
//  expired, revoked, or cannot be verified to a root authority:
ftp.RequireSslCertVerify := 1;

//  You may also set a requirement.  In this example,
//  the certificate's Common Name (CN) must match the
//  required string exactly:
ftp.SetSslCertRequirement('subjectcn','Chilkat Software, Inc.');

//  Connect and login to the FTP server.
success := ftp.Connect();
if (success <> 1) then
  begin
    ShowMessage(ftp.LastErrorText);

  end
else
  begin
    //  LastErrorText contains information even when
    //  successful. This allows you to visually verify
    //  that the secure connection actually occurred.
    Memo1.Lines.Add(ftp.LastErrorText);
  end;

//  After logging on, you may examine the FTP server's cert:

cert := ftp.GetSslServerCert();
if (cert = nil ) then
  begin
    ShowMessage('No server certificate!');
  end
else
  begin
    //  Display the distinguished name of the SSL cert.
    ShowMessage(cert.SubjectDN);
  end;

ShowMessage('Secure FTP Channel Established!');

//  Do whatever you're doing to do ...
//  upload files, download files, etc...

ftp.Disconnect();
end;