Pascal (Lazarus/Delphi)

Sign PDF with Long-Term Validation (LTV Enabled)

See more PDF Signatures Examples

This example demonstrates how to a sign a PDF with long-term validation (LTV) enabled.

Note: This example requires Chilkat v9.5.0.85 or greater.

Pascal (Lazarus/Delphi)

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;
  pdf: TPdf;
  json: TJsonObject;
  cert: TCert;

begin
  success := False;

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

  pdf := TPdf.Create;

  //  Load a PDF to be signed.
  //  The "hello.pdf" is available at https://chilkatsoft.com/hello.pdf
  success := pdf.LoadFile('qa_data/pdf/hello.pdf');
  if (success = False) then
    begin
      WriteLn(pdf.LastErrorText);
      Exit;
    end;

  //  Options for signing are specified in JSON.
  json := TJsonObject.Create;

  //  In most cases, the signingCertificateV2 and signingTime attributes are required.
  json.UpdateInt('signingCertificateV2',1);
  json.UpdateInt('signingTime',1);

  //  Add the "ltvOcsp" instruction to the JSON passed to SignPdf.
  //  This is what causes Chilkat to create an LTV-enabled signature.
  //  
  //  If we are signing a PDF that already has signatures, then the existing signatures
  //  are automatically verified, and Chilkat will do OCSP certificate status checking (if possible) 
  //  for those certs in existing signatures (including certs in the certificate chains) 
  //  that do not yet have a valid OCSP response in the DSS (Document Security Store).
  //  Chilkat will add the OCSP responses to the /OCSPs in the Document Security Store (/DSS).
  //  Also, and certificates from existing signatures not yet in the DSS are added to the /Certs 
  //  in the DSS.
  //  
  //  Also, the "ltvOcsp" causes Chilkat to add the pdfRevocationInfoArchival authenticated attribute
  //  to the CMS signature.  The pdfRevocationInfoArchival attribute (1.2.840.113583.1.1.8)
  //  contains OCSP responses and the CRL for the issuer of the signing certificate.
  //  Therefore, Chilkat will send an OCSP request to the signing certificate's OCSP URl (if one exists)
  //  and will download the CRL from the issuer certificate's CRL Distribution Point (if one exists).
  json.UpdateBool('ltvOcsp',True);

  //  -----------------------------------------------------------------------------------
  //  Note: If Chilkat produces a signed PDF, but the signature is not LTV-enabled,
  //  the cause might be related to a failure to download CRL's or OCSP requests.
  //  See Possible Solution for Failure to Produce LTV-enabled PDF Signature
  //  -----------------------------------------------------------------------------------
  //  You can add the following to UncommonOptions to get detailed information about the CRL and OCSP requests
  //  You shouldn't set the following logging options unless there is a need, because it adds a large amount of information to the LastErrorText.
  pdf.UncommonOptions := 'LOG_OCSP_HTTP,LOG_CRL_HTTP';

  //  Define the appearance of the signature.
  json.UpdateInt('page',1);
  json.UpdateString('appearance.y','top');
  json.UpdateString('appearance.x','left');
  json.UpdateString('appearance.fontScale','10.0');
  json.UpdateString('appearance.text[0]','Digitally signed by: cert_cn');
  json.UpdateString('appearance.text[1]','current_dt');
  json.UpdateString('appearance.text[2]','This is an LTV-enabled signature.');

  //  Load the signing certificate. (Use your own certificate.)
  cert := TCert.Create;
  success := cert.LoadPfxFile('qa_data/pfx/myPdfSigningCert.pfx','pfxPassword');
  if (success = False) then
    begin
      WriteLn(cert.LastErrorText);
      Exit;
    end;

  //  Tell the pdf object to use the certificate for signing.
  success := pdf.SetSigningCert(cert);
  if (success = False) then
    begin
      WriteLn(pdf.LastErrorText);
      Exit;
    end;

  success := pdf.SignPdf(json,'qa_output/hello_ltv_signed.pdf');
  if (success = False) then
    begin
      WriteLn(pdf.LastErrorText);
      Exit;
    end;

  WriteLn('The PDF has been successfully cryptographically signed with long-term validation.');

  //  If you open the Signature Panel in Adobe Acrobat, it will indicate that the signature is LTV enabled
  //  as shown here:
  //  (image:https://example-code.com/images/ltv_signature.jpg/endImage)


  pdf.Free;
  json.Free;
  cert.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.