Refactor AesGcmSecretKey Class

lib/src/impl_ffi/impl_ffi.aescbc.dart

@@ -114,7 +114,7 @@ final class _StaticAesCbcSecretKeyImpl implements StaticAesCbcSecretKeyImpl {
   }
 }
 
-final class _AesCbcSecretKeyImpl extends AesCbcSecretKeyImpl {
+final class _AesCbcSecretKeyImpl implements AesCbcSecretKeyImpl {
   final Uint8List _key;
   _AesCbcSecretKeyImpl(this._key);
 

lib/src/impl_ffi/impl_ffi.aesctr.dart

@@ -221,7 +221,7 @@ final class _StaticAesCtrSecretKeyImpl implements StaticAesCtrSecretKeyImpl {
   }
 }
 
-final class _AesCtrSecretKeyImpl extends AesCtrSecretKeyImpl {
+final class _AesCtrSecretKeyImpl implements AesCtrSecretKeyImpl {
   final Uint8List _key;
   _AesCtrSecretKeyImpl(this._key);
 

lib/src/impl_ffi/impl_ffi.aesgcm.dart

@@ -16,19 +16,19 @@
 
 part of 'impl_ffi.dart';
 
-Future<AesGcmSecretKey> aesGcm_importRawKey(List<int> keyData) async =>
-    _AesGcmSecretKey(_aesImportRawKey(keyData));
+Future<AesGcmSecretKeyImpl> aesGcm_importRawKey(List<int> keyData) async =>
+    _AesGcmSecretKeyImpl(_aesImportRawKey(keyData));
 
-Future<AesGcmSecretKey> aesGcm_importJsonWebKey(
+Future<AesGcmSecretKeyImpl> aesGcm_importJsonWebKey(
   Map<String, dynamic> jwk,
 ) async =>
-    _AesGcmSecretKey(_aesImportJwkKey(
+    _AesGcmSecretKeyImpl(_aesImportJwkKey(
       jwk,
       expectedJwkAlgSuffix: 'GCM',
     ));
 
-Future<AesGcmSecretKey> aesGcm_generateKey(int length) async =>
-    _AesGcmSecretKey(_aesGenerateKey(length));
+Future<AesGcmSecretKeyImpl> aesGcm_generateKey(int length) async =>
+    _AesGcmSecretKeyImpl(_aesGenerateKey(length));
 
 Future<Uint8List> _aesGcmEncryptDecrypt(
   List<int> key,
@@ -111,9 +111,28 @@ Future<Uint8List> _aesGcmEncryptDecrypt(
   });
 }
 
-class _AesGcmSecretKey implements AesGcmSecretKey {
+final class _StaticAesGcmSecretKeyImpl implements StaticAesGcmSecretKeyImpl {
+  const _StaticAesGcmSecretKeyImpl();
+
+  @override
+  Future<AesGcmSecretKeyImpl> importRawKey(List<int> keyData) async {
+    return await aesGcm_importRawKey(keyData);
+  }
+
+  @override
+  Future<AesGcmSecretKeyImpl> importJsonWebKey(Map<String, dynamic> jwk) async {
+    return await aesGcm_importJsonWebKey(jwk);
+  }
+
+  @override
+  Future<AesGcmSecretKeyImpl> generateKey(int length) async {
+    return await aesGcm_generateKey(length);
+  }
+}
+
+final class _AesGcmSecretKeyImpl implements AesGcmSecretKeyImpl {
   final Uint8List _key;
-  _AesGcmSecretKey(this._key);
+  _AesGcmSecretKeyImpl(this._key);
 
   @override
   String toString() {

lib/src/impl_ffi/impl_ffi.dart

@@ -80,4 +80,7 @@ final class _WebCryptoImpl implements WebCryptoImpl {
 
   @override
   final aesCtrSecretKey = const _StaticAesCtrSecretKeyImpl();
+
+  @override
+  final aesGcmSecretKey = const _StaticAesGcmSecretKeyImpl();
 }

lib/src/impl_interface/impl_interface.aescbc.dart

@@ -20,7 +20,7 @@ abstract interface class StaticAesCbcSecretKeyImpl {
   Future<AesCbcSecretKeyImpl> generateKey(int length);
 }
 
-abstract class AesCbcSecretKeyImpl {
+abstract interface class AesCbcSecretKeyImpl {
   Future<Uint8List> encryptBytes(List<int> data, List<int> iv);
   Future<Uint8List> decryptBytes(List<int> data, List<int> iv);
   Stream<Uint8List> encryptStream(Stream<List<int>> data, List<int> iv);

lib/src/impl_interface/impl_interface.aesctr.dart

@@ -20,7 +20,7 @@ abstract interface class StaticAesCtrSecretKeyImpl {
   Future<AesCtrSecretKeyImpl> generateKey(int length);
 }
 
-abstract class AesCtrSecretKeyImpl {
+abstract interface class AesCtrSecretKeyImpl {
   Future<Uint8List> encryptBytes(List<int> data, List<int> counter, int length);
   Future<Uint8List> decryptBytes(List<int> data, List<int> counter, int length);
   Stream<Uint8List> encryptStream(Stream<List<int>> data, List<int> counter, int length);

lib/src/impl_interface/impl_interface.aesgcm.dart

@@ -0,0 +1,28 @@
+// Copyright 2020 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+part of 'impl_interface.dart';
+
+abstract interface class StaticAesGcmSecretKeyImpl {
+  Future<AesGcmSecretKeyImpl> importRawKey(List<int> keyData);
+  Future<AesGcmSecretKeyImpl> importJsonWebKey(Map<String, dynamic> jwk);
+  Future<AesGcmSecretKeyImpl> generateKey(int length);
+}
+
+abstract interface class AesGcmSecretKeyImpl {
+  Future<Uint8List> encryptBytes(List<int> data, List<int> iv, {List<int>? additionalData, int? tagLength});
+  Future<Uint8List> decryptBytes(List<int> data, List<int> iv, {List<int>? additionalData, int? tagLength});
+  Future<Uint8List> exportRawKey();
+  Future<Map<String, dynamic>> exportJsonWebKey();
+}

lib/src/impl_interface/impl_interface.dart

@@ -20,6 +20,7 @@ import 'dart:async';
 
 part 'impl_interface.aescbc.dart';
 part 'impl_interface.aesctr.dart';
+part 'impl_interface.aesgcm.dart';
 
 /// Interface to be provided by platform implementations.
 ///
@@ -40,4 +41,5 @@ part 'impl_interface.aesctr.dart';
 abstract interface class WebCryptoImpl {
   StaticAesCbcSecretKeyImpl get aesCbcSecretKey;
   StaticAesCtrSecretKeyImpl get aesCtrSecretKey;
+  StaticAesGcmSecretKeyImpl get aesGcmSecretKey;
 }

lib/src/impl_js/impl_js.aesctr.dart

@@ -66,7 +66,7 @@ final class _StaticAesCtrSecretKeyImpl implements StaticAesCtrSecretKeyImpl {
   }
 }
 
-final class _AesCtrSecretKeyImpl extends AesCtrSecretKeyImpl {
+final class _AesCtrSecretKeyImpl implements AesCtrSecretKeyImpl {
   final subtle.JSCryptoKey _key;
   _AesCtrSecretKeyImpl(this._key);
 

lib/src/impl_js/impl_js.aesgcm.dart

@@ -18,8 +18,8 @@ part of 'impl_js.dart';
 
 const _aesGcmAlgorithm = subtle.Algorithm(name: 'AES-GCM');
 
-Future<AesGcmSecretKey> aesGcm_importRawKey(List<int> keyData) async {
-  return _AesGcmSecretKey(await _importKey(
+Future<AesGcmSecretKeyImpl> aesGcm_importRawKey(List<int> keyData) async {
+  return _AesGcmSecretKeyImpl(await _importKey(
     'raw',
     keyData,
     _aesGcmAlgorithm,
@@ -28,28 +28,47 @@ Future<AesGcmSecretKey> aesGcm_importRawKey(List<int> keyData) async {
   ));
 }
 
-Future<AesGcmSecretKey> aesGcm_importJsonWebKey(
+Future<AesGcmSecretKeyImpl> aesGcm_importJsonWebKey(
   Map<String, dynamic> jwk,
 ) async {
-  return _AesGcmSecretKey(await _importJsonWebKey(
+  return _AesGcmSecretKeyImpl(await _importJsonWebKey(
     jwk,
     _aesGcmAlgorithm,
     _usagesEncryptDecrypt,
     'secret',
   ));
 }
 
-Future<AesGcmSecretKey> aesGcm_generateKey(int length) async {
-  return _AesGcmSecretKey(await _generateKey(
+Future<AesGcmSecretKeyImpl> aesGcm_generateKey(int length) async {
+  return _AesGcmSecretKeyImpl(await _generateKey(
     _aesGcmAlgorithm.update(length: length),
     _usagesEncryptDecrypt,
     'secret',
   ));
 }
 
-class _AesGcmSecretKey implements AesGcmSecretKey {
+final class _StaticAesGcmSecretKeyImpl implements StaticAesGcmSecretKeyImpl {
+  const _StaticAesGcmSecretKeyImpl();
+
+  @override
+  Future<AesGcmSecretKeyImpl> importRawKey(List<int> keyData) async {
+    return await aesGcm_importRawKey(keyData);
+  }
+
+  @override
+  Future<AesGcmSecretKeyImpl> importJsonWebKey(Map<String, dynamic> jwk) async {
+    return await aesGcm_importJsonWebKey(jwk);
+  }
+
+  @override
+  Future<AesGcmSecretKeyImpl> generateKey(int length) async {
+    return await aesGcm_generateKey(length);
+  }
+}
+
+final class _AesGcmSecretKeyImpl implements AesGcmSecretKeyImpl {
   final subtle.JSCryptoKey _key;
-  _AesGcmSecretKey(this._key);
+  _AesGcmSecretKeyImpl(this._key);
 
   @override
   String toString() {

lib/src/impl_js/impl_js.dart

@@ -66,4 +66,7 @@ final class _WebCryptoImpl implements WebCryptoImpl {
 
   @override
   final aesCtrSecretKey = const _StaticAesCtrSecretKeyImpl();
+
+  @override
+  final aesGcmSecretKey = const _StaticAesGcmSecretKeyImpl();
 }

lib/src/impl_stub.dart

@@ -207,14 +207,6 @@ Future<RsaOaepPublicKey> rsaOaepPublicKey_importJsonWebKey(
 
 //---------------------- AES-GCM
 
-Future<AesGcmSecretKey> aesGcm_importRawKey(List<int> keyData) =>
-    throw _notImplemented;
-
-Future<AesGcmSecretKey> aesGcm_importJsonWebKey(Map<String, dynamic> jwk) =>
-    throw _notImplemented;
-
-Future<AesGcmSecretKey> aesGcm_generateKey(int length) => throw _notImplemented;
-
 //---------------------- ECDH
 
 Future<EcdhPrivateKey> ecdhPrivateKey_importPkcs8Key(

lib/src/impl_stub/impl_stub.aesgcm.dart

@@ -0,0 +1,31 @@
+// Copyright 2020 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+part of 'impl_stub.dart';
+
+final class _StaticAesGcmSecretKeyImpl implements StaticAesGcmSecretKeyImpl {
+  const _StaticAesGcmSecretKeyImpl();
+
+  @override
+  Future<AesGcmSecretKeyImpl> importRawKey(List<int> keyData) =>
+    throw UnimplementedError('Not implemented');
+
+  @override
+  Future<AesGcmSecretKeyImpl> importJsonWebKey(Map<String, dynamic> jwk) =>
+    throw UnimplementedError('Not implemented');
+
+  @override
+  Future<AesGcmSecretKeyImpl> generateKey(int length) =>
+    throw UnimplementedError('Not implemented');
+}

lib/src/impl_stub/impl_stub.dart

@@ -18,6 +18,7 @@ import 'package:webcrypto/src/impl_interface/impl_interface.dart';
 
 part 'impl_stub.aescbc.dart';
 part 'impl_stub.aesctr.dart';
+part 'impl_stub.aesgcm.dart';
 
 const WebCryptoImpl webCryptImpl = _WebCryptoImpl();
 
@@ -29,4 +30,7 @@ final class _WebCryptoImpl implements WebCryptoImpl {
 
   @override
   final aesCtrSecretKey = const _StaticAesCtrSecretKeyImpl();
+
+  @override
+  final aesGcmSecretKey = const _StaticAesGcmSecretKeyImpl();
 }

lib/src/webcrypto/webcrypto.aesgcm.dart

@@ -32,9 +32,10 @@ part of 'webcrypto.dart';
 /// [1]: https://csrc.nist.gov/pubs/sp/800/38/d/final
 /// [2]: https://tools.ietf.org/html/rfc7517
 /// [3]: https://en.wikipedia.org/wiki/Authenticated_encryption
-@sealed
-abstract class AesGcmSecretKey {
-  AesGcmSecretKey._(); // keep the constructor private.
+final class AesGcmSecretKey {
+  final AesGcmSecretKeyImpl _impl;
+
+  AesGcmSecretKey._(this._impl); // keep the constructor private.
 
   /// Import an [AesGcmSecretKey] from raw [keyData].
   ///
@@ -66,8 +67,9 @@ abstract class AesGcmSecretKey {
   /// // Decrypt message (requires the same iv)
   /// print(utf8.decode(await k.decryptBytes(c, iv))); // hello world
   /// ```
-  static Future<AesGcmSecretKey> importRawKey(List<int> keyData) {
-    return impl.aesGcm_importRawKey(keyData);
+  static Future<AesGcmSecretKey> importRawKey(List<int> keyData) async {
+    final impl = await webCryptImpl.aesGcmSecretKey.importRawKey(keyData);
+    return AesGcmSecretKey._(impl);
   }
 
   /// Import an [AesGcmSecretKey] from [JSON Web Key][1].
@@ -102,8 +104,9 @@ abstract class AesGcmSecretKey {
   /// ```
   ///
   /// [1]: https://tools.ietf.org/html/rfc7517
-  static Future<AesGcmSecretKey> importJsonWebKey(Map<String, dynamic> jwk) {
-    return impl.aesGcm_importJsonWebKey(jwk);
+  static Future<AesGcmSecretKey> importJsonWebKey(Map<String, dynamic> jwk) async {
+    final impl = await webCryptImpl.aesGcmSecretKey.importJsonWebKey(jwk);
+    return AesGcmSecretKey._(impl);
   }
 
   /// Generate a random [AesGcmSecretKey].
@@ -122,8 +125,9 @@ abstract class AesGcmSecretKey {
   /// // Generate a new random AES-GCM secret key for AES-256.
   /// final key = await AesGcmSecretKey.generate(256);
   /// ```
-  static Future<AesGcmSecretKey> generateKey(int length) {
-    return impl.aesGcm_generateKey(length);
+  static Future<AesGcmSecretKey> generateKey(int length) async {
+    final impl = await webCryptImpl.aesGcmSecretKey.generateKey(length);
+    return AesGcmSecretKey._(impl);
   }
 
   /// Encrypt [data] with this [AesCbcSecretKey] using AES in
@@ -218,7 +222,8 @@ abstract class AesGcmSecretKey {
     List<int> iv, {
     List<int>? additionalData,
     int? tagLength = 128,
-  });
+  }) =>
+      _impl.encryptBytes(data, iv, additionalData: additionalData, tagLength: tagLength);
 
   // TODO: Document this method, notice that [data] must be concatenation of
   //       ciphertext and authentication tag.
@@ -228,7 +233,8 @@ abstract class AesGcmSecretKey {
     List<int> iv, {
     List<int>? additionalData,
     int? tagLength = 128,
-  });
+  }) =>
+      _impl.decryptBytes(data, iv, additionalData: additionalData, tagLength: tagLength);
 
   /// Export [AesGcmSecretKey] as raw bytes.
   ///
@@ -250,7 +256,7 @@ abstract class AesGcmSecretKey {
   /// // If we wanted to we could import the key as follows:
   /// // key = await AesGcmSecretKey.importRawKey(secretBytes);
   /// ```
-  Future<Uint8List> exportRawKey();
+  Future<Uint8List> exportRawKey() => _impl.exportRawKey();
 
   /// Export [AesGcmSecretKey] as [JSON Web Key][1].
   ///
@@ -274,5 +280,5 @@ abstract class AesGcmSecretKey {
   /// ```
   ///
   /// [1]: https://tools.ietf.org/html/rfc7517
-  Future<Map<String, dynamic>> exportJsonWebKey();
+  Future<Map<String, dynamic>> exportJsonWebKey() => _impl.exportJsonWebKey();
 }