Dart

Add a Document Timestamp Signature to an already-signed PDF

See more PDF Signatures Examples

Demonstrates how to add a document timestamp signature to an already-signed PDF.

Note: This example requires Chilkat v9.5.0.99 or greater.

Dart

import 'package:chilkat/chilkat.dart';

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

  final pdf = CkPdf();

  // Load the PDF that has already been signed.
  try {
    pdf.loadFile('qa_data/pdf/helloWorld_signed.pdf');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  final json = CkJsonObject();

  json.updateBool('invisibleSignature', true);
  json.updateString('subFilter', '/ETSI.RFC3161');

  json.updateBool('timestampToken.enabled', true);

  // In this example, we'll use a free TSA server (timestamp.digicert.com), but you may want to use your own timestamp authority server.
  json.updateString('timestampToken.tsaUrl', 'http://timestamp.digicert.com');

  // If the timestamp server requires a username/password, do the following.  Otherwise omit the following few lines of code.
  json.updateString('timestampToken.tsaUsername', 'the_tsa_username');
  json.updateString('timestampToken.tsaPassword', 'the_tsa_password');

  // When requesting the timestamp token, ask the server to include its certificate in the timestamp token response.
  // This allows for the timestamp server's certificate to be included in the LTV validation (i.e. if the timestamp server
  // has an OCSP URL, then Chilkat will also do the OCSP request for the timestamp server's certificate.)
  json.updateBool('timestampToken.requestTsaCert', true);

  try {
    pdf.signPdf(json, 'c:/temp/qa_output/helloWorld_signed_2.pdf');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  print('Successfully added a Document Timestamp Signature to the PDF');
}