Dart

CAdES BES Attached (Opaque) Signature

See more Encryption Examples

Demonstrates how to create a CAdES BES attached signature file (.p7m). This is a PKCS7 signature format (known as an opaque, or "attached" signature) where the file data is embedded within the signature file. The signature verification both verifies the signature and extracts the original data.

(A "detached" signature is where the original data is NOT included within the PKCS7 signature format.)

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();

  // Use a digital certificate and private key from a PFX file (.pfx or .p12).
  final pfxPath = 'qa_data/pfx/myCertAndPrivateKey.p12';
  final pfxPassword = 'password';

  final cert = CkCert();
  try {
    cert.loadPfxFile(pfxPath, pfxPassword);
  } 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;

  // To sign with SHA1, set the HashAlgorithm property to "sha1"
  crypt.hashAlgorithm = 'sha1';

  // To sign with SHA256, set the HashAlgorithm property to "SHA256".
  crypt.hashAlgorithm = 'sha256';

  // Other hash algorithm choices are "md5", "md2", "sha384", and "sha512"

  // We can sign any type of file, creating a .p7m as output.
  // The .p7m contains the signature and also embeds the data of the file that is signed.
  final inFile = 'qa_data/json/sample.json';
  final sigFile = 'qa_output/signature.p7m';

  // -----------------------------------------------------------------------------------------
  // Also see Chilkat's online tool to examine a .p7m and generate code to duplicate the .p7m
  // -----------------------------------------------------------------------------------------

  // Create the CAdES-BES attached signature, which contains the original data.
  try {
    crypt.createP7M(inFile, sigFile);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Verify the .p7m file and extract the original file from the .p7m. 
  final extractedToFilePath = 'qa_output/sample.json';
  try {
    crypt.verifyP7M(sigFile, extractedToFilePath);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  print('Success!');
}