Dart

Create a CAdES-T Signature

See more CAdES Examples

Demonstrates how to create a signature with an external timestamp that certifies the time of signing. This requires an online TSA (Time Stamping Authority) service that is capable of producing RFC 3161 compliant timestamps.

Note: This example requires Chilkat v9.5.0.78 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 crypt = CkCrypt2();

  // This example will use a certificate + private key from a .pfx/.p12 file.
  // On Windows systems, it is also possible to use certs on smartcards/usb tokens or certs pre-installed in the Windows registry.
  final cert = CkCert();

  final pfxPath = 'qa_data/pfx/myCertAndKey.p12';
  final pfxPassword = 'test123';

  try {
    cert.loadPfxFile(pfxPath, pfxPassword);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  crypt.setSigningCert(cert);

  // Use SHA-256 rather than the default of SHA-1
  crypt.hashAlgorithm = 'sha256';

  // Create JSON that tells Chilkat what signing attributes to include:
  final attrs = CkJsonObject();
  attrs.updateBool('contentType', true);
  attrs.updateBool('signingTime', true);
  attrs.updateBool('messageDigest', true);
  attrs.updateBool('signingCertificateV2', true);

  // A CAdES-T signature is one that includes a timestampToken created by an online TSA (time stamping authority).
  // We must include the TSA's URL, as well as a few options to indicate what is desired.
  // Except for the TSA URL, the options shown here are typically what you would need.
  attrs.updateBool('timestampToken.enabled', true);
  attrs.updateString('timestampToken.tsaUrl', 'https://freetsa.org/tsr');
  attrs.updateBool('timestampToken.addNonce', false);
  attrs.updateBool('timestampToken.requestTsaCert', true);
  attrs.updateString('timestampToken.hashAlg', 'sha256');

  crypt.signingAttributes = attrs.emit();

  final inFile = 'qa_data/json/sample.json';
  final outFile = 'qa_output/sample_cades_t.p7m';

  // This creates the CAdES-T signature.  During the signature creation, it
  // communicates with the TSA to get a timestampToken.
  try {
    crypt.createP7M(inFile, outFile);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  print('Success.');
}