Lazarus Pascal Requires Chilkat v11.7.0+

Encrypt a PDF for a Certificate Instead of a Password

See more PDF Protection Examples

Demonstrates certificate security, where a PDF is encrypted for one or more recipients and each opens it with their own certificate and private key. No password is involved. Only the public certificate of a recipient is needed to encrypt. Each recipient has its own permissions, and the changeSecurity permission gives a recipient owner rights. PreLoadCheck tells an application that a file is certificate-encrypted and which certificates can open it. A PDF that cannot be opened, because no matching certificate and private key were provided, fails to load. 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.Cert,
  Chilkat.JsonObject;

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

procedure RunDemo;
var
  success: Boolean;
  recipient: TCert;
  pdf: TPdf;
  json: TJsonObject;
  jsonOut: TJsonObject;
  reader: TPdf;
  info: TJsonObject;
  myCert: TCert;
  empty: TJsonObject;
  loadedInfo: TJsonObject;

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

  //  The recipient's certificate.  Only the public certificate is needed to encrypt.
  recipient := TCert.Create;
  success := recipient.LoadFromFile('qa_data/certs/recipient.cer');
  if (success = False) then
    begin
      WriteLn(recipient.LastErrorText);
      Exit;
    end;

  pdf := TPdf.Create;
  success := pdf.LoadFile('qa_data/pdf/two_page_memo.pdf');
  if (success = False) then
    begin
      WriteLn(pdf.LastErrorText);
      Exit;
    end;

  //  Call AddEncryptCert once for each recipient.
  success := pdf.AddEncryptCert(recipient);
  if (success = False) then
    begin
      WriteLn(pdf.LastErrorText);
      Exit;
    end;

  //  recipientPermissions[0] belongs to the first certificate added.  changeSecurity gives that
  //  recipient owner rights, so the file can be managed later.
  json := TJsonObject.Create;
  json.UpdateString('method','certificate');
  json.UpdateBool('recipientPermissions[0].changeSecurity',True);

  jsonOut := TJsonObject.Create;
  success := pdf.Protection('encrypt',json,jsonOut);
  if (success = False) then
    begin
      WriteLn(pdf.LastErrorText);
      Exit;
    end;
  WriteLn('method: ' + jsonOut.StringOf('pending.method'));
  WriteLn('algorithm: ' + jsonOut.StringOf('pending.algorithm'));
  WriteLn('recipients: ' + jsonOut.SizeOfArray('pending.recipients'));

  success := pdf.WriteFile('qa_output/memo_for_recipient.pdf');
  if (success = False) then
    begin
      WriteLn(pdf.LastErrorText);
      Exit;
    end;

  //  PreLoadCheck says how the file is protected, without loading it.
  reader := TPdf.Create;
  info := TJsonObject.Create;
  success := reader.PreLoadCheck('qa_output/memo_for_recipient.pdf',info);
  if (success = False) then
    begin
      WriteLn(reader.LastErrorText);
      Exit;
    end;
  WriteLn('saved file, method: ' + info.StringOf('method'));
  WriteLn('saved file, recipients: ' + info.SizeOfArray('recipients'));

  //  The recipient opens it with the certificate and its private key, here from a .pfx file.
  //  (On Windows, a certificate that is installed in the Windows certificate store with its private
  //  key is found automatically when the PDF is loaded, and SetDecryptCert is not needed for it.)
  myCert := TCert.Create;
  success := myCert.LoadPfxFile('qa_data/pfx/recipient.pfx','pfx-password');
  if (success = False) then
    begin
      WriteLn(myCert.LastErrorText);
      Exit;
    end;
  success := reader.SetDecryptCert(myCert);
  if (success = False) then
    begin
      WriteLn(reader.LastErrorText);
      Exit;
    end;
  success := reader.LoadFile('qa_output/memo_for_recipient.pdf');
  if (success = False) then
    begin
      WriteLn(reader.LastErrorText);
      Exit;
    end;

  empty := TJsonObject.Create;
  loadedInfo := TJsonObject.Create;
  success := reader.Protection('getInfo',empty,loadedInfo);
  if (success = False) then
    begin
      WriteLn(reader.LastErrorText);
      Exit;
    end;
  WriteLn('opened with: ' + loadedInfo.StringOf('loaded.openedWith'));
  WriteLn('pages: ' + reader.NumPages);

  //  Sample output:

  //  method: certificate
  //  algorithm: aes-256
  //  recipients: 1
  //  saved file, method: certificate
  //  saved file, recipients: 1
  //  opened with: certificate
  //  pages: 2


  recipient.Free;
  pdf.Free;
  json.Free;
  jsonOut.Free;
  reader.Free;
  info.Free;
  myCert.Free;
  empty.Free;
  loadedInfo.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.