Dart

Create CMS (PKCS7) Detached MIME Signature

Demonstrates how to add a CMS detached signature to MIME. 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 mime = CkMime();

  // Load a certificate w/ private key for signing.
  final cert = CkCert();
  try {
    cert.loadPfxFile('qa_data/pfx/ecc256_12345.p12', '12345');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  print('Cert: ${cert.subjectDN}');

  // Create a simple MIME message to be signed:
  mime.addHeaderField('Subject', 'This is a test');
  mime.addHeaderField('MyCustomHeader', 'abc123');
  mime.contentType = 'text/plain';
  mime.setBody('This is a plain-text body.');

  // Examine the MIME prior to signing:
  print('--- MIME prior to signing ---');
  print(mime.getMime());

  // The MIME prior to signing looks like this:

  // Subject: This is a test
  // MyCustomHeader: abc123
  // Content-Type: text/plain; format=flowed
  // 
  // This is a plain-text body.

  // Use SHA256 as the hash algorithm in the CMS signature.
  mime.signingHashAlg = 'SHA256';

  // Add a detached signature:
  try {
    mime.addDetachedSignature(cert);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Examine the MIME with detached signature:
  print('--- MIME with detached signature ---');
  print(mime.getMime());

  // Content-Type: multipart/signed; boundary="----=_NextPart_6e3_c655_9641494d.b4f00501";
  //  protocol="application/x-pkcs7-signature";
  //  micalg=sha256
  // 
  // ------=_NextPart_6e3_c655_9641494d.b4f00501
  // Subject: This is a test
  // MyCustomHeader: abc123
  // Content-Type: text/plain; format=flowed
  // 
  // This is a plain-text body.
  // ------=_NextPart_6e3_c655_9641494d.b4f00501
  // Content-Transfer-Encoding: base64
  // Content-Type: application/x-pkcs7-signature; name="smime.p7s"
  // Content-Disposition: attachment; filename="smime.p7s"
  // 
  // MIID7AYJKoZIhvcNAQcCoIID3TCCA9kCAQExDzANBglghkgBZQMEAgEFADALBgkqhkiG9w0BBwGg
  // ggJxMIICbTCCAhOgAwIBAgIJAJuS2kgOoyr+MAkGByqGSM49BAEwWzELMAkGA1UEBhMCQVUxEzAR
  // BgNVBAgTClNvbWUtU3RhdGUxITAfBgNVBAoTGEludGVybmV0IFdpZGdpdHMgUHR5IEx0ZDEUMBIG
  // A1UEAxMLZWNjMjU2LXRlc3QwHhcNMTYwODIzMTU0OTM5WhcNNDQwMTA4MTU0OTM5WjBbMQswCQYD
  // VQQGEwJBVTETMBEGA1UECBMKU29tZS1TdGF0ZTEhMB8GA1UEChMYSW50ZXJuZXQgV2lkZ2l0cyBQ
  // dHkgTHRkMRQwEgYDVQQDEwtlY2MyNTYtdGVzdDBZMBMGByqGSM49AgEGCCqGSM49AwEHA0IABARy
  // Hd86A7+qQ4DlIfKynZaFGdGLpkU3GlQwqaVD6GIJg3QIDhaWEksYtZ9OWjNHn9a6+i/P9o5/NrdI
  // SP0VWDWjgcAwgb0wHQYDVR0OBBYEFGmd2DfK4c3VBTVn8ebKH2BTmRicMIGNBgNVHSMEgYUwgYKA
  // FGmd2DfK4c3VBTVn8ebKH2BTmRicoV+kXTBbMQswCQYDVQQGEwJBVTETMBEGA1UECBMKU29tZS1T
  // dGF0ZTEhMB8GA1UEChMYSW50ZXJuZXQgV2lkZ2l0cyBQdHkgTHRkMRQwEgYDVQQDEwtlY2MyNTYt
  // dGVzdIIJAJuS2kgOoyr+MAwGA1UdEwQFMAMBAf8wCQYHKoZIzj0EAQNJADBGAiEAhuiwGy0lZKtK
  // LA13Ffc8AMTK7NsePPSfs0clXlZUR78CIQDXsJXpYsJ7tlTeockrK+6099sG/gGFTRPiQYU8juyf
  // LzGCAT8wggE7AgEBMGgwWzELMAkGA1UEBhMCQVUxEzARBgNVBAgTClNvbWUtU3RhdGUxITAfBgNV
  // BAoTGEludGVybmV0IFdpZGdpdHMgUHR5IEx0ZDEUMBIGA1UEAxMLZWNjMjU2LXRlc3QCCQCbktpI
  // DqMq/jANBglghkgBZQMEAgEFAKBpMBgGCSqGSIb3DQEJAzELBgkqhkiG9w0BBwEwHAYJKoZIhvcN
  // AQkFMQ8XDTIyMDUwODE0MzM1NFowLwYJKoZIhvcNAQkEMSIEIMvNpYuymLvF68aFFe+l3NEQTdkB
  // 7T8U6/j+Y5FgDlIUMAoGCCqGSM49BAMCBEYwRAIgQ6migEn3Le9ciIVUP/qc2JZAJZWjpulJXY9Q
  // IZJ3XK0CIGZwpLOgiv7ES8958hqT9a/q7aPc1xmkaZHtsat/k+Ki
  // 
  // ------=_NextPart_6e3_c655_9641494d.b4f00501--
}