Dart Requires Chilkat v11.0.0+

Duplicate OpensSSL to Sign File and Output Binary DER

See more OpenSSL Examples

This example duplicates the following:

openssl smime -sign -in INPUT.xml -signer SIGN.PEM -passin pass:MYPASS -outform der -binary -nodetach -out SIGNED.P7M

Note: Although "smime" is the OpenSSL command, it's not actually producing S/MIME. The arguments "-outform der -binary" indicates that the output is binary DER (i.e. the PKCS7 binary signature). The input can be any type of file: XML, PDF, JPG, ... *anything*...

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();

  // Load the PEM containing cert + private key.
  final pem = CkPem();
  try {
    pem.loadPemFile('qa_data/pem/myPem.pem', 'password');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  final privkey = CkPrivateKey();
  try {
    pem.privateKeyAt(0, privkey);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  final cert = CkCert();
  try {
    pem.certAt(0, cert);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  try {
    crypt.setSigningCert2(cert, privkey);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Alternatively, we could use a .pfx/.p12 file.
  // (Chilkat also supports other formats/sources for cert/private keys...)
  final certFromP12 = CkCert();
  try {
    certFromP12.loadPfxFile('qa_data/p12/myP12.p12', 'password');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // The certificate, when loaded from a .pfx/.p12, will automatically 
  // include the associated private key, assuming it's present in the .p12.
  // We don't have to explicitly provide the private key as in the
  // lines of code above that use the PEM file.
  try {
    crypt.setSigningCert(certFromP12);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Create the opaque signature (PKCS7 binary DER that contains both the signature and original file data).
  try {
    crypt.createP7M('qa_data/infile.anything', 'qa_output/outfile.p7m');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  print('Success.');
}