Dart

Add EncapsulatedTimestamp to Already-Signed XML

See more XML Digital Signatures Examples

Demonstrates how to add an EncapsulatedTimestamp to an existing XML signature.

Note: This example requires Chilkat v9.5.0.90 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.

  // Note: We cannot load the already-signed XML into a Chilkat XML object because it would re-format the XML when re-emitted.
  // (i.e. indentation and whitespace could change, and it would invalidate the existing signature.)
  // We must use a StringBuilder.
  final sbXml = CkStringBuilder();
  try {
    sbXml.loadFile('qa_data/xml_dsig_valid_samples/encapsulatedTimestamp_not_yet_added.xml', 'utf-8');
  } on ChilkatException {
    print('Failed to load the XML file.');
    return;
  }

  final dsig = CkXmlDSig();
  try {
    dsig.loadSignatureSb(sbXml);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  if (dsig.hasEncapsulatedTimeStamp()) {
    print('This signed XML already has an EncapsulatedTimeStamp');
    return;
  }

  // Specify the timestamping authority URL
  final json = CkJsonObject();
  json.updateString('timestampToken.tsaUrl', 'http://timestamp.digicert.com');
  json.updateBool('timestampToken.requestTsaCert', true);

  // Call AddEncapsulatedTimeStamp to add the EncapsulatedTimeStamp to the signature.
  // Note: If the signed XML contains multiple signatures, the signature modified is the one 
  // indicated by the dsig.Selector property.
  final sbOut = CkStringBuilder();
  try {
    dsig.addEncapsulatedTimeStamp(json, sbOut);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  sbOut.writeFile('qa_output/addedEncapsulatedTimeStamp.xml', 'utf-8', false);

  // The EncapsulatedTimeStamp can be validated when validating the signature by adding the VerifyEncapsulatedTimeStamp
  // keyword to UncommonOptions.  See here:

  // ----------------------------------------
  // Verify the signatures we just produced...
  final verifier = CkXmlDSig();
  try {
    verifier.loadSignatureSb(sbOut);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Add "VerifyEncapsulatedTimeStamp" to the UncommonOptions to also verify any EncapsulatedTimeStamps
  verifier.uncommonOptions = 'VerifyEncapsulatedTimeStamp';

  final numSigs = verifier.numSignatures;
  var verifyIdx = 0;
  while (verifyIdx < numSigs) {
    verifier.selector = verifyIdx;
    try {
      verifier.verifySignature(true);
    } on ChilkatException catch (e) {
      print(e.lastErrorText);
      return;
    }

    verifyIdx++;
  }

  print('All signatures were successfully verified.');
}