Create Password Protected Zip containing a Single File.

Create a password-protected .zip containing a single file. (This uses the older Zip 2.0 encryption scheme, which is weaker and not as secure as AES encryption, which Chilkat Zip also supports.)

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

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

...

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

  end;

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

  end;

zip.SetPassword('secret');
zip.PasswordProtect := 1;

saveExtraPath := 0;
success := zip.AppendOneFileOrDir('c:/temp/hamlet.xml',saveExtraPath);

success := zip.WriteZipAndClose();
if (success <> 1) then
  begin
    ShowMessage(zip.LastErrorText);

  end;

ShowMessage('Zip Created!');
end;