Dart Requires Chilkat v11.0.0+

Sign Mexico Pedimento

See more Misc Examples

Add a signature to a Mexico pedimento file. 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.

  // This is the contents before signing:

  // 500|1|3621|4199800|400||
  // 601|3621|4199800|400|IN|1||EKU9003173C9|EKU9003173C9FRNN09|1||
  // 507|4199800|IM|2006-7888">
  // 507|4199800|MS|2">
  // 800|4199800|1">
  // 801|M3621037.222|1|5|011|

  // This is the contents after signing

  // 500|1|3621|4199800|400||
  // 601|3621|4199800|400|IN|1||EKU9003173C9|EKU9003173C9FRNN09|1||
  // 507|4199800|IM|2006-7888">
  // 507|4199800|MS|2">
  // 800|4199800|1|fhP2Ker54D2+3+UZch23F0E72 .... 9qNSPIuAqpj524qLZbbA==|30001000000500003416|
  // 801|M3621037.222|1|5|011|

  // First create the text to be signed.
  final bCRLF = true;
  final sb = CkStringBuilder();
  // Use CRLF line endings.
  sb.appendLine('500|1|3621|4199800|400||', bCRLF);
  sb.appendLine('601|3621|4199800|400|IN|1||EKU9003173C9|EKU9003173C9FRNN09|1||', bCRLF);
  sb.appendLine('507|4199800|IM|2006-7888">', bCRLF);
  sb.appendLine('507|4199800|MS|2">', bCRLF);

  // Generate the MD5 hash of what we have so far..
  final md5Base64 = sb.getHash('md5', 'base64', 'utf-8');
  print('MD5 hash = $md5Base64');

  // Complete the original file.
  // After signing, we'll update the BASE64_SIGNATURE and CERT_SERIAL
  sb.appendLine('800|4199800|1|BASE64_SIGNATURE|CERT_SERIAL|', bCRLF);
  sb.appendLine('801|M3621037.222|1|5|011|', bCRLF);

  // We're going to sign the MD5 hash using the private key.
  final privKey = CkPrivateKey();
  try {
    privKey.loadAnyFormatFile('qa_data/certs/mexico_test/Certificados_de_Prueba/Certificados_Pruebas/Personas Morales/EKU9003173C9_20230517223532/CSD_EKU9003173C9_20230517223903/CSD_Sucursal_1_EKU9003173C9_20230517_223850.key', '12345678a');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Generate the ASN.1 to be signed.

  // <sequence>
  //     <sequence>
  //         <oid>1.2.840.113549.2.5</oid>
  //         <null/>
  //     </sequence>
  //     <octets>SwxHfaJhG+N3pPqay6UzVA==</octets>
  // </sequence>

  final xml = CkXml();
  xml.tag = 'sequence';
  xml.updateChildContent('sequence|oid', '1.2.840.113549.2.5');
  xml.updateChildContent('sequence|null', '');
  xml.updateChildContent('octets', md5Base64);

  final asn = CkAsn();
  asn.loadAsnXml(xml.getXml());
  print('ASN.1 = ${asn.getEncodedDer('base64')}');

  // Sign with the private key.
  final rsa = CkRsa();
  try {
    rsa.usePrivateKey(privKey);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Create the opaque signature.
  final bdSig = CkBinData();
  bdSig.appendEncoded(asn.getEncodedDer('base64'), 'base64');
  try {
    rsa.signRawBd(bdSig);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // bd now contains the opaque signature, which embeds the ASN.1, which contains the MD5 hash.
  // We're going to add this line:
  // 800|4199800|1|BASE64_SIGNATURE|CERT_SERIAL_NUM|

  final cert = CkCert();
  try {
    cert.loadFromFile('qa_data/certs/mexico_test/Certificados_de_Prueba/Certificados_Pruebas/Personas Morales/EKU9003173C9_20230517223532/CSD_EKU9003173C9_20230517223903/CSD_Sucursal_1_EKU9003173C9_20230517_223850.cer');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  final serialHex = cert.serialNumber;
  // The serial in hex form looks like this:   3330303031303030303030353030303033343136
  // Decode to us-ascii.
  final sbSerial = CkStringBuilder();
  sbSerial.decodeAndAppend(serialHex, 'hex', 'us-ascii');
  print('serial number in us-ascii: ${sbSerial.getAsString()}');

  var numReplaced = sb.replace('CERT_SERIAL', sbSerial.getAsString());
  numReplaced = sb.replace('BASE64_SIGNATURE', bdSig.getEncoded('base64'));

  print('------------------------------------');
  print('Result:');
  print(sb.getAsString());
}