Add new platform layer

lib/src/platform.dart

@@ -0,0 +1,114 @@
+// Copyright (c) 2020
+// Author: Hugo Pointcheval
+
+import 'dart:typed_data';
+
+import 'package:flutter/services.dart';
+
+import 'cipher.dart';
+
+/// Represents a platform, and is usefull to calling
+/// methods from a specific platform.
+class Platform {
+  /// Contains the channel for platform specific code.
+  static const MethodChannel _channel = const MethodChannel('native.crypto');
+
+  /// Calls native code.
+  static Future<T> call<T>(String method, [Map<String, dynamic> arguments]) {
+    return _channel.invokeMethod(method, arguments);
+  }
+
+  /// Calls native PBKDF2.
+  ///
+  /// Takes password and salt as parameters.
+  /// And optionnally keyLength in bytes, number of iterations and hash algorithm.
+  ///
+  /// Returns a key as [Uint8List].
+  Future<Uint8List> pbkdf2(
+    String password,
+    String salt, {
+    int keyLength: 32,
+    int iteration: 10000,
+    String algorithm: 'sha256',
+  }) async {
+    final Uint8List key = await call('pbkdf2', <String, dynamic>{
+      'password': password,
+      'salt': salt,
+      'keyLength': keyLength,
+      'iteration': iteration,
+      'algorithm': algorithm,
+    });
+    return key;
+  }
+
+  /// Generates a random key.
+  ///
+  /// Takes size in bits.
+  ///
+  /// Returns a key as [Uint8List].
+  Future<Uint8List> keygen(int size) async {
+    final Uint8List key = await call('keygen', <String, dynamic>{
+      'size': size,
+    });
+
+    return key;
+  }
+
+  /// Generates an RSA key pair.
+  ///
+  /// Takes size in bits.
+  ///
+  /// Returns a key pair as list of [Uint8List], the public key is the
+  /// first element, and the private is the last.
+  Future<List<Uint8List>> rsaKeypairGen(int size) async {
+    final List<Uint8List> keypair =
+        await call('rsaKeypairGen', <String, dynamic>{
+      'size': size,
+    });
+
+    return keypair;
+  }
+
+  /// Encrypts data with a secret key and algorithm.
+  ///
+  /// Takes data, key, algorithm, mode and padding as parameters.
+  ///
+  /// Encrypts data and returns cipher text
+  /// and IV as a list of [Uint8List].
+  Future<List<Uint8List>> encrypt(
+    Uint8List data,
+    Uint8List key,
+    String algorithm,
+    CipherParameters parameters,
+  ) async {
+    final List<Uint8List> payload = await call('encrypt', <String, dynamic>{
+      'data': data,
+      'key': key,
+      'algorithm': algorithm,
+      'mode': parameters.mode.index,
+      'padding': parameters.padding.index,
+    });
+    return payload;
+  }
+
+  /// Decrypts a payload with a secret key and algorithm.
+  ///
+  /// The payload must be a list of `Uint8List`
+  /// with encrypted cipher as first and IV as second member.
+  Future<Uint8List> decrypt(
+    List<Uint8List> payload,
+    Uint8List key,
+    String algorithm,
+    CipherParameters parameters,
+  ) async {
+    final Uint8List data =
+        await _channel.invokeMethod('decrypt', <String, dynamic>{
+      'payload': payload,
+      'key': key,
+      'algorithm': algorithm,
+      'mode': parameters.mode.index,
+      'padding': parameters.padding.index,
+    });
+    return data;
+  }
+}