encryptPhrase function

Future<String> encryptPhrase(String phrase, String password, [ Map<String, dynamic>? options ])

Implementation

Future<String> encryptPhrase(
  String phrase,
  String password, [
  Map<String, dynamic>? options,
]) async {
  Uint8List uuid = Uint8List(16);
  Uuid uuidParser = const Uuid()..v4buffer(uuid);

  String salt = randomAsHex(64);
  List<int> iv = randomAsU8a(16);
  String kdf = 'scrypt';
  int level = 8192;
  int n = kdf == 'pbkdf2' ? 262144 : level;
  if (options == null) {
    kdf = 'scrypt';
    level = 8192;
    n = kdf == 'pbkdf2' ? 262144 : level;
  } else {
    kdf = options['kdf'] is String ? options['kdf'] : 'scrypt';
    level = options['level'] is int ? options['level'] : 8192;
    n = kdf == 'pbkdf2' ? 262144 : level;
  }

  Map<String, dynamic> kdfParams = {
    'salt': salt,
    'n': n,
    'r': 8,
    'p': 1,
    'dklen': 32
  };

  List<int> encodedPassword = utf8.encode(password);
  _KeyDerivator derivator = getDerivedKey(kdf, kdfParams);
  List<int> derivedKey = derivator.deriveKey(encodedPassword);

  List<int> ciphertextBytes = _encryptPhrase(derivator,
      Uint8List.fromList(encodedPassword), Uint8List.fromList(iv), phrase);

  List<int> macBuffer = derivedKey.sublist(16, 32) +
      ciphertextBytes +
      iv +
      ALGO_IDENTIFIER.codeUnits;

  String mac = (SHA256()
      .update(Uint8List.fromList(derivedKey))
      .update(macBuffer)
      .digest()
      .toHex());

  Map<String, dynamic> map = {
    'crypto': {
      'cipher': 'aes-128-ctr',
      'cipherparams': {'iv': Uint8List.fromList(iv).toHex()},
      'ciphertext': Uint8List.fromList(ciphertextBytes).toHex(),
      'kdf': kdf,
      'kdfparams': kdfParams,
      'mac': mac,
    },
    'id': uuidParser.v4buffer(uuid),
    'version': 3,
  };
  String result = json.encode(map);
  return result;
}