(Delphi DLL) Socket TLS Mutual Authentication (Client-Side Certificate)

This example demonstrates how to provide a client-side certificate, also known as "two-way authentication" or "mutual authentication" for servers that require a client certificate.

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, Socket;

...

procedure TForm1.Button1Click(Sender: TObject);
var
sock: HCkSocket;
success: Boolean;
bTls: Boolean;
port: Integer;
maxWaitMs: Integer;

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

sock := CkSocket_Create();

// Set the certificate to be used for mutual TLS authentication
// (i.e. sets the client-side certificate for two-way TLS authentication)
success := CkSocket_SetSslClientCertPfx(sock,'/home/bob/pfxFiles/myClientSideCertWithPrivateKey.pfx','pfxPassword');
if (success <> True) then
  begin
    Memo1.Lines.Add(CkSocket__lastErrorText(sock));
    Exit;
  end;

// Note: The certificate used for the client-side of TLS mutual authentication
// must have the associated private key available. (.pfx/.p12 files typically store both
// the certificate and associated private key.)

// Establish the connection using the socket object (with client certificate authentication).
bTls := True;
port := 443;
maxWaitMs := 5000;
success := CkSocket_Connect(sock,'www.example.com',port,bTls,maxWaitMs);
if (success <> True) then
  begin
    Memo1.Lines.Add('Connect Failure Error Code: ' + IntToStr(CkSocket_getConnectFailReason(sock)));
    Memo1.Lines.Add(CkSocket__lastErrorText(sock));
    Exit;
  end;

// At this point, the Socket object is connected and authenticated using the client-side cert

// ...
// ..

CkSocket_Dispose(sock);

end;