Dart

Sign JSON to Create CAdES P7S Bytes

See more CAdES Examples

Demonstrates how to sign JSON using a certificate + private key from a .p12/.pfx to create a CAdES P7S byte array. Dart

import 'package:chilkat/chilkat.dart';

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

  final crypt = CkCrypt2();

  final cert = CkCert();
  try {
    cert.loadPfxFile('qa_data/pfx/cert_test123.pfx', 'test123');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Tell the crypt component to use this cert.
  try {
    crypt.setSigningCert(cert);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // The CadesEnabled property applies to all methods that create PKCS7 signatures. 
  // To create a CAdES-BES signature, set this property equal to true. 
  crypt.cadesEnabled = true;

  crypt.hashAlgorithm = 'sha256';

  final jsonSigningAttrs = CkJsonObject();
  jsonSigningAttrs.updateInt('contentType', 1);
  jsonSigningAttrs.updateInt('signingTime', 1);
  jsonSigningAttrs.updateInt('messageDigest', 1);
  jsonSigningAttrs.updateInt('signingCertificateV2', 1);
  crypt.signingAttributes = jsonSigningAttrs.emit();

  // By default, all the certs in the chain of authentication are included in the signature.
  // If desired, we can choose to only include the signing certificate:
  crypt.includeCertChain = false;

  // Create the CAdES-BES attached signature, which contains the original data.
  crypt.charset = 'utf-8';
  final cadesP7s = crypt.opaqueSignString('{ "abc": 123}');
  if (!crypt.lastMethodSuccess) {
    print(crypt.lastErrorText);
    return;
  }

  // Verify the signature and extract the original JSON:
  final String originalJson;
  try {
    originalJson = crypt.opaqueVerifyString(cadesP7s);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  print('Original JSON: $originalJson');

  print('Success!');
}