run aes encryption in background isolate.

bin/kdbx.dart

@@ -91,7 +91,7 @@ abstract class KdbxFileCommand extends Command<void> {
     final keyFile = argResults['keyfile'] as String;
     final keyFileData =
         keyFile == null ? null : await File(keyFile).readAsBytes();
-    ;
+
     final file = await KdbxFormat(Argon2Test()).read(
       bytes,
       Credentials.composite(ProtectedValue.fromString(password), keyFileData),

lib/src/crypto/key_encrypter_kdf.dart

@@ -2,6 +2,7 @@ import 'dart:convert';
 import 'dart:typed_data';
 
 import 'package:crypto/crypto.dart' as crypto;
+import 'package:isolate/isolate_runner.dart';
 import 'package:kdbx/kdbx.dart';
 import 'package:kdbx/src/crypto/argon2.dart';
 import 'package:kdbx/src/internal/byte_utils.dart';
@@ -91,7 +92,7 @@ class KeyEncrypterKdf {
         break;
       case KdfType.Aes:
         _logger.fine('Must be using aes');
-        return encryptAes(key, kdfParameters);
+        return await encryptAes(key, kdfParameters);
     }
     throw UnsupportedError(
         'unsupported KDF Type UUID ${ByteUtils.toHexList(uuid)}.');
@@ -112,16 +113,43 @@ class KeyEncrypterKdf {
     ));
   }
 
-  Uint8List encryptAes(Uint8List key, VarDictionary kdfParameters) {
+  Future<Uint8List> encryptAes(
+      Uint8List key, VarDictionary kdfParameters) async {
     final encryptionKey = KdfField.salt.read(kdfParameters);
     final rounds = KdfField.rounds.read(kdfParameters);
     assert(encryptionKey.length == 32);
+    return await encryptAesAsync(EncryptAesArgs(encryptionKey, key, rounds));
+  }
+
+  static Future<Uint8List> encryptAesAsync(EncryptAesArgs args) async {
+    final runner = await IsolateRunner.spawn();
+    try {
+      _logger
+          .finest('Starting encryptAes for ${args.rounds} rounds in isolate.');
+      return await runner.run(_encryptAesSync, args);
+    } finally {
+      _logger.finest('Done aes encrypt.');
+      await runner.kill();
+    }
+  }
+
+  static Uint8List _encryptAesSync(EncryptAesArgs args) {
     final cipher = ECBBlockCipher(AESFastEngine())
-      ..init(true, KeyParameter(encryptionKey));
-    var transformedKey = key;
-    for (int i = 0; i < rounds; i++) {
+      ..init(true, KeyParameter(args.encryptionKey));
+    var transformedKey = args.key;
+
+    final rounds = args.rounds;
+    for (var i = 0; i < rounds; i++) {
       transformedKey = AesHelper.processBlocks(cipher, transformedKey);
     }
     return crypto.sha256.convert(transformedKey).bytes as Uint8List;
   }
 }
+
+class EncryptAesArgs {
+  EncryptAesArgs(this.encryptionKey, this.key, this.rounds);
+
+  final Uint8List encryptionKey;
+  final Uint8List key;
+  final int rounds;
+}

lib/src/crypto/protected_value.dart

@@ -35,14 +35,14 @@ class ProtectedValue implements StringValue {
   ProtectedValue(this._value, this._salt);
 
   factory ProtectedValue.fromString(String value) {
-    final Uint8List valueBytes = utf8.encode(value) as Uint8List;
-    final Uint8List salt = _randomBytes(valueBytes.length);
+    final valueBytes = utf8.encode(value) as Uint8List;
+    final salt = _randomBytes(valueBytes.length);
 
     return ProtectedValue(_xor(valueBytes, salt), salt);
   }
 
   factory ProtectedValue.fromBinary(Uint8List value) {
-    final Uint8List salt = _randomBytes(value.length);
+    final salt = _randomBytes(value.length);
     return ProtectedValue(_xor(value, salt), salt);
   }
 
@@ -63,7 +63,7 @@ class ProtectedValue implements StringValue {
   static Uint8List _xor(Uint8List a, Uint8List b) {
     assert(a.length == b.length);
     final ret = Uint8List(a.length);
-    for (int i = 0; i < a.length; i++) {
+    for (var i = 0; i < a.length; i++) {
       ret[i] = a[i] ^ b[i];
     }
     return ret;

lib/src/internal/crypto_utils.dart

@@ -1,10 +1,7 @@
 import 'dart:typed_data';
 
-import 'package:logging/logging.dart';
 import 'package:pointycastle/export.dart';
 
-final _logger = Logger('crypto_utils');
-
 /// https://gist.github.com/proteye/e54eef1713e1fe9123d1eb04c0a5cf9b
 class AesHelper {
   static const CBC_MODE = 'CBC';
@@ -87,11 +84,9 @@ class AesHelper {
   static Uint8List processBlocks(BlockCipher cipher, Uint8List inp) {
     final out = Uint8List(inp.lengthInBytes);
 
-    _logger.finest('Starting processBlocks. (${inp.lengthInBytes})');
     for (var offset = 0; offset < inp.lengthInBytes;) {
       offset += cipher.processBlock(inp, offset, out, offset);
     }
-    _logger.finest('Done processBlocks.');
 
     return out;
   }

lib/src/kdbx_format.dart

@@ -162,7 +162,7 @@ class KdbxFile {
       final gen = ProtectedSaltGenerator(streamKey);
 
       body.meta.headerHash.set(headerHash.buffer);
-      body.writeV3(writer, this, gen);
+      await body.writeV3(writer, this, gen);
     } else if (header.versionMajor <= 4) {
       final headerBytes = writer.output.toBytes();
       writer.writeBytes(headerHash);
@@ -227,16 +227,15 @@ class KdbxBody extends KdbxNode {
   final KdbxMeta meta;
   final KdbxGroup rootGroup;
 
-  void writeV3(WriterHelper writer, KdbxFile kdbxFile,
-      ProtectedSaltGenerator saltGenerator) {
+  Future<void> writeV3(WriterHelper writer, KdbxFile kdbxFile,
+      ProtectedSaltGenerator saltGenerator) async {
     final xml = generateXml(saltGenerator);
     final xmlBytes = utf8.encode(xml.toXmlString());
-    final Uint8List compressedBytes =
-        (kdbxFile.header.compression == Compression.gzip
+    final compressedBytes = (kdbxFile.header.compression == Compression.gzip
         ? GZipCodec().encode(xmlBytes)
         : xmlBytes) as Uint8List;
 
-    final encrypted = _encryptV3(kdbxFile, compressedBytes);
+    final encrypted = await _encryptV3(kdbxFile, compressedBytes);
     writer.writeBytes(encrypted);
   }
 
@@ -246,8 +245,7 @@ class KdbxBody extends KdbxNode {
     final xml = generateXml(saltGenerator);
     kdbxFile.header.writeInnerHeader(bodyWriter);
     bodyWriter.writeBytes(utf8.encode(xml.toXmlString()) as Uint8List);
-    final Uint8List compressedBytes =
-        (kdbxFile.header.compression == Compression.gzip
+    final compressedBytes = (kdbxFile.header.compression == Compression.gzip
         ? GZipCodec().encode(bodyWriter.output.toBytes())
         : bodyWriter.output.toBytes()) as Uint8List;
     final encrypted = _encryptV4(
@@ -260,15 +258,16 @@ class KdbxBody extends KdbxNode {
     writer.writeBytes(transformed);
   }
 
-  Uint8List _encryptV3(KdbxFile kdbxFile, Uint8List compressedBytes) {
+  Future<Uint8List> _encryptV3(
+      KdbxFile kdbxFile, Uint8List compressedBytes) async {
     final byteWriter = WriterHelper();
     byteWriter.writeBytes(
         kdbxFile.header.fields[HeaderFields.StreamStartBytes].bytes);
     HashedBlockReader.writeBlocks(ReaderHelper(compressedBytes), byteWriter);
     final bytes = byteWriter.output.toBytes();
 
-    final masterKey =
-        KdbxFormat._generateMasterKeyV3(kdbxFile.header, kdbxFile.credentials);
+    final masterKey = await KdbxFormat._generateMasterKeyV3(
+        kdbxFile.header, kdbxFile.credentials);
     final encrypted = KdbxFormat._encryptDataAes(masterKey, bytes,
         kdbxFile.header.fields[HeaderFields.EncryptionIV].bytes);
     return encrypted;
@@ -369,7 +368,7 @@ class KdbxFormat {
     final reader = ReaderHelper(input);
     final header = KdbxHeader.read(reader);
     if (header.versionMajor == 3) {
-      return _loadV3(header, reader, credentials);
+      return await _loadV3(header, reader, credentials);
     } else if (header.versionMajor == 4) {
       return await _loadV4(header, reader, credentials);
     } else {
@@ -380,10 +379,10 @@ class KdbxFormat {
     }
   }
 
-  KdbxFile _loadV3(
-      KdbxHeader header, ReaderHelper reader, Credentials credentials) {
+  Future<KdbxFile> _loadV3(
+      KdbxHeader header, ReaderHelper reader, Credentials credentials) async {
 //    _getMasterKeyV3(header, credentials);
-    final masterKey = _generateMasterKeyV3(header, credentials);
+    final masterKey = await _generateMasterKeyV3(header, credentials);
     final encryptedPayload = reader.readRemaining();
     final content = _decryptContent(header, masterKey, encryptedPayload);
     final blocks = HashedBlockReader.readBlocks(ReaderHelper(content));
@@ -442,7 +441,7 @@ class KdbxFormat {
     final writer = WriterHelper();
     final reader = ReaderHelper(data);
     const blockSize = 1024 * 1024;
-    int blockIndex = 0;
+    var blockIndex = 0;
     while (true) {
       final blockData = reader.readBytesUpTo(blockSize);
       final calculatedHash = _hmacHashForBlock(hmacKey, blockIndex, blockData);
@@ -481,7 +480,7 @@ class KdbxFormat {
 
   Uint8List hmacBlockTransformer(Uint8List hmacKey, ReaderHelper reader) {
     final ret = <int>[];
-    int blockIndex = 0;
+    var blockIndex = 0;
     while (true) {
       final blockHash = reader.readBytes(32);
       final blockLength = reader.readUint32();
@@ -654,23 +653,17 @@ class KdbxFormat {
     return AesHelper.processBlocks(encryptCypher, paddedBytes);
   }
 
-  static Uint8List _generateMasterKeyV3(
-      KdbxHeader header, Credentials credentials) {
+  static Future<Uint8List> _generateMasterKeyV3(
+      KdbxHeader header, Credentials credentials) async {
     final rounds = ReaderHelper.singleUint64(
         header.fields[HeaderFields.TransformRounds].bytes);
     final seed = header.fields[HeaderFields.TransformSeed].bytes;
     final masterSeed = header.fields[HeaderFields.MasterSeed].bytes;
     _logger.finer(
         'Rounds: $rounds (${ByteUtils.toHexList(header.fields[HeaderFields.TransformRounds].bytes)})');
+    final transformedKey = await KeyEncrypterKdf.encryptAesAsync(
+        EncryptAesArgs(seed, credentials.getHash(), rounds));
 
-    final cipher = ECBBlockCipher(AESFastEngine())
-      ..init(true, KeyParameter(seed));
-    final pwHash = credentials.getHash();
-    var transformedKey = pwHash;
-    for (int i = 0; i < rounds; i++) {
-      transformedKey = AesHelper.processBlocks(cipher, transformedKey);
-    }
-    transformedKey = crypto.sha256.convert(transformedKey).bytes as Uint8List;
     final masterKey = crypto.sha256
         .convert(Uint8List.fromList(masterSeed + transformedKey))
         .bytes as Uint8List;

pubspec.yaml

@@ -19,6 +19,7 @@ dependencies:
   meta: '>=1.0.0 <2.0.0'
   clock: '>=1.0.0 <2.0.0'
   convert: '>=2.0.0 <3.0.0'
+  isolate: '>=2.0.3 <3.0.0'
 
   collection: '>=1.14.0 <2.0.0'
 

test/kdbx4_test.dart

@@ -93,7 +93,7 @@ void main() {
       final file = await kdbxFormat.read(
           data, Credentials(ProtectedValue.fromString('asdf')));
       expect(file.body.rootGroup.entries, hasLength(1));
-    });
+    }, skip: 'Takes tooo long, too many iterations.');
   });
   group('Writing', () {
     test('Create and save', () async {