Delphi ActiveX

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 Delphi ActiveX Downloads

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Delphi ActiveX

var
success: Integer;
ftp: TChilkatFtp2;

begin
success := 0;

ftp := TChilkatFtp2.Create(Self);

ftp.Hostname := 'ftp.example.com';
ftp.Username := 'myFtpLogin';

ftp.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.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.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.TlsPinSet := 'sha256//YLh1dUR9y6Kja30RrAn7JKnbQG/uEtLMkBgFF2Fuihg=';

success := ftp.Connect();
if (success = 0) then
  begin
    Memo1.Lines.Add(ftp.LastErrorText);
    Exit;
  end;

//  SslServerCertVerified reports whether the certificate chain was successfully verified.
if (ftp.SslServerCertVerified) then
  begin
    Memo1.Lines.Add('The server certificate was verified.');
  end;

success := ftp.Disconnect();
if (success = 0) then
  begin
    Memo1.Lines.Add(ftp.LastErrorText);
    Exit;
  end;