Dart

Get PDF Signer Certs

See more PDF Signatures Examples

This example demonstrates how to validate the signatures in a PDF and also shows how to get 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 a PDF that has cryptographic signatures to be validated
  try {
    pdf.loadFile('qa_data/pdf/sign_testing_1/helloSigned2.pdf');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Each time we verify a signature, information about the signature is written into
  // sigInfo (replacing whatever sigInfo previously contained).
  final sigInfo = CkJsonObject();

  // Iterate over each signature and validate each.
  final numSignatures = pdf.numSignatures;
  var validated = false;
  final cert = CkCert();
  var i = 0;
  while (i < numSignatures) {
    validated = true;
    try {
      pdf.verifySignature(i, sigInfo);
    } on ChilkatException {
      validated = false;
    }
    print('Signature $i validated: $validated');

    // After calling VerifySignature, you can get the signer certificate by calling
    // GetSignerCert with the same index. 
    try {
      pdf.getSignerCert(i, cert);
      print('PDF signer certificate: ${cert.subjectDN}');
    } on ChilkatException {
      // pdf.getSignerCert() failed; continue anyway.
    }

    i++;
  }

  print('Finished.');
}