(Delphi DLL) 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.

Chilkat for Delphi Downloads Chilkat non-ActiveX DLL for Delphi Chilkat ActiveX DLL for Delphi * The examples here use the non-ActiveX DLL.

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Ftp2, Cert;

...

procedure TForm1.Button1Click(Sender: TObject);
var
ftp: HCkFtp2;
success: Boolean;
cert: HCkCert;

begin
// This example requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

ftp := CkFtp2_Create();

CkFtp2_putHostname(ftp,'ftp.myftpserver.com');
CkFtp2_putUsername(ftp,'myUsername');
CkFtp2_putPassword(ftp,'myPassword');

// Establish an AUTH SSL secure channel after connection
// on the standard FTP port 21.
CkFtp2_putAuthSsl(ftp,True);

// The Ssl property is for establishing an implicit SSL connection
// on port 990.  Do not set it.
CkFtp2_putSsl(ftp,False);

// 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:
CkFtp2_putRequireSslCertVerify(ftp,True);

// You may also set a requirement.  In this example,
// the certificate's Common Name (CN) must match the
// required string exactly:
CkFtp2_SetSslCertRequirement(ftp,'subjectcn','Chilkat Software, Inc.');

// Connect and login to the FTP server.
success := CkFtp2_Connect(ftp);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkFtp2__lastErrorText(ftp));
    Exit;
  end
else
  begin
    // LastErrorText contains information even when
    // successful. This allows you to visually verify
    // that the secure connection actually occurred.
    Memo1.Lines.Add(CkFtp2__lastErrorText(ftp));
  end;

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

cert := CkFtp2_GetSslServerCert(ftp);
if (CkFtp2_getLastMethodSuccess(ftp) <> True) then
  begin
    Memo1.Lines.Add('No server certificate!');
  end
else
  begin
    // Display the distinguished name of the SSL cert.
    Memo1.Lines.Add(CkCert__subjectDN(cert));
  end;

Memo1.Lines.Add('Secure FTP Channel Established!');

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

success := CkFtp2_Disconnect(ftp);

CkFtp2_Dispose(ftp);

end;