Open Zip and Save Password Protected

Open a .zip (non-encrypted) and then save it password-protected.

Download Chilkat 32-bit Zip ActiveX (.msi) (includes objects for .zip, .gz, .bz2, and .Z)

Download All 32-bit Chilkat ActiveX Components (.zip)

Download All 64-bit Chilkat ActiveX Components (.zip)

uses
    Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
    Dialogs, StdCtrls,
    ChilkatZip2Lib_TLB,
    OleCtrls;

...

procedure TForm1.Button1Click(Sender: TObject);
var
zip: TChilkatZip2;
success: Integer;

begin
zip := TChilkatZip2.Create(Self);

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

success := zip.OpenZip('test.zip');
if (success <> 1) then
  begin
    ShowMessage(zip.LastErrorText);
    Exit;
  end;

//  Set a password and indicate that password protection
//  should be used when writing the .zip
zip.EncryptPassword := 'secret';
zip.PasswordProtect := 1;

//  Write the zip (overwrites test.zip)
success := zip.WriteZipAndClose();
if (success <> 1) then
  begin
    ShowMessage(zip.LastErrorText);
    Exit;
  end;

ShowMessage('Zip Re-Written with Password Protection!');
end;