Lazarus Pascal Requires Chilkat v11.7.0+

Choose the PDF Encryption Algorithm: AES-256, AES-128 or RC4

See more PDF Protection Examples

Demonstrates the algorithmChoice option of the encrypt operation. aes-256 is the default and the one to use unless an older reader must open the file. aes-128 is for readers that predate AES-256. rc4-128 and rc4-40 are broken ciphers kept only for very old readers. Each algorithm needs a minimum PDF version, and the file header is raised to it when the PDF is saved, never lowered. A PDF saved with RC4 is written with a classic cross-reference table so that those old readers can parse it. Lazarus Pascal

program ChilkatDemo;

// Demonstrates using the Chilkat Pascal wrapper via the C bridge DLL.
// Builds as a console application under Lazarus (FPC) or Delphi.

{$IFDEF FPC}
  {$MODE DELPHI}
{$ENDIF}
{$APPTYPE CONSOLE}

uses
  {$IFDEF UNIX}
  cthreads,
  {$ENDIF}
  SysUtils,
  CkDllLoader,
  Chilkat.Pdf,
  Chilkat.JsonObject;

// ---------------------------------------------------------------------------

procedure RunDemo;
var
  success: Boolean;
  json: TJsonObject;
  jsonOut: TJsonObject;
  info: TJsonObject;
  pdf1: TPdf;
  pdf2: TPdf;
  pdf3: TPdf;

begin
  success := False;

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

  //  The PDF used in this example is available at two_page_memo.pdf

  json := TJsonObject.Create;
  jsonOut := TJsonObject.Create;
  info := TJsonObject.Create;

  //  AES-256, the default.  Saved as PDF 1.7 with Adobe extension level 8.
  pdf1 := TPdf.Create;
  success := pdf1.LoadFile('qa_data/pdf/two_page_memo.pdf');
  if (success = False) then
    begin
      WriteLn(pdf1.LastErrorText);
      Exit;
    end;
  pdf1.UserPassword := 'user-secret';
  pdf1.OwnerPassword := 'owner-secret';
  json.UpdateString('algorithmChoice','aes-256');
  success := pdf1.Protection('encrypt',json,jsonOut);
  if (success = False) then
    begin
      WriteLn(pdf1.LastErrorText);
      Exit;
    end;
  WriteLn('aes-256 will be saved as PDF ' + jsonOut.StringOf('pending.pdfVersion') + ', Adobe extension level ' + jsonOut.IntOf('pending.adobeExtensionLevel'));
  success := pdf1.WriteFile('qa_output/memo_aes256.pdf');
  if (success = False) then
    begin
      WriteLn(pdf1.LastErrorText);
      Exit;
    end;
  success := pdf1.PreLoadCheck('qa_output/memo_aes256.pdf',info);
  if (success = False) then
    begin
      WriteLn(pdf1.LastErrorText);
      Exit;
    end;
  WriteLn('  saved file: ' + info.StringOf('algorithm') + ', PDF ' + info.StringOf('pdfVersion'));

  //  AES-128, for readers that predate AES-256.  Saved as PDF 1.6.
  pdf2 := TPdf.Create;
  success := pdf2.LoadFile('qa_data/pdf/two_page_memo.pdf');
  if (success = False) then
    begin
      WriteLn(pdf2.LastErrorText);
      Exit;
    end;
  pdf2.UserPassword := 'user-secret';
  pdf2.OwnerPassword := 'owner-secret';
  json.UpdateString('algorithmChoice','aes-128');
  success := pdf2.Protection('encrypt',json,jsonOut);
  if (success = False) then
    begin
      WriteLn(pdf2.LastErrorText);
      Exit;
    end;
  WriteLn('aes-128 will be saved as PDF ' + jsonOut.StringOf('pending.pdfVersion'));
  success := pdf2.WriteFile('qa_output/memo_aes128.pdf');
  if (success = False) then
    begin
      WriteLn(pdf2.LastErrorText);
      Exit;
    end;
  success := pdf2.PreLoadCheck('qa_output/memo_aes128.pdf',info);
  if (success = False) then
    begin
      WriteLn(pdf2.LastErrorText);
      Exit;
    end;
  WriteLn('  saved file: ' + info.StringOf('algorithm') + ', PDF ' + info.StringOf('pdfVersion'));

  //  RC4-128, a broken cipher, only for readers too old for AES.  Saved as PDF 1.4.
  pdf3 := TPdf.Create;
  success := pdf3.LoadFile('qa_data/pdf/two_page_memo.pdf');
  if (success = False) then
    begin
      WriteLn(pdf3.LastErrorText);
      Exit;
    end;
  pdf3.UserPassword := 'user-secret';
  pdf3.OwnerPassword := 'owner-secret';
  json.UpdateString('algorithmChoice','rc4-128');
  success := pdf3.Protection('encrypt',json,jsonOut);
  if (success = False) then
    begin
      WriteLn(pdf3.LastErrorText);
      Exit;
    end;
  WriteLn('rc4-128 will be saved as PDF ' + jsonOut.StringOf('pending.pdfVersion'));
  success := pdf3.WriteFile('qa_output/memo_rc4_128.pdf');
  if (success = False) then
    begin
      WriteLn(pdf3.LastErrorText);
      Exit;
    end;
  success := pdf3.PreLoadCheck('qa_output/memo_rc4_128.pdf',info);
  if (success = False) then
    begin
      WriteLn(pdf3.LastErrorText);
      Exit;
    end;
  WriteLn('  saved file: ' + info.StringOf('algorithm') + ', PDF ' + info.StringOf('pdfVersion'));

  //  Sample output:

  //  aes-256 will be saved as PDF 1.7, Adobe extension level 8
  //    saved file: aes-256, PDF 1.7
  //  aes-128 will be saved as PDF 1.6
  //    saved file: aes-128, PDF 1.6
  //  rc4-128 will be saved as PDF 1.4
  //    saved file: rc4-128, PDF 1.4


  json.Free;
  jsonOut.Free;
  info.Free;
  pdf1.Free;
  pdf2.Free;
  pdf3.Free;

end;

// ---------------------------------------------------------------------------

begin

  try
    RunDemo;
  except
    on E: Exception do
      WriteLn('Unhandled exception: ', E.ClassName, ': ', E.Message);
  end;

  WriteLn;
  {$IFDEF MSWINDOWS}
  WriteLn('Press Enter to exit...');
  ReadLn;
  {$ENDIF}
end.