added AesCbcCryptor, ICryptor

pubnub/lib/src/core/crypto/crypto.dart

@@ -21,3 +21,22 @@ abstract class ICryptoModule {
   List<int> encryptFileData(CipherKey key, List<int> input);
   List<int> decryptFileData(CipherKey key, List<int> input);
 }
+
+/// @nodoc
+abstract class ICryptor {
+  String get identifier;
+  EncryptedData encrypt(List<int> input);
+  List<int> decrypt(EncryptedData input);
+}
+
+class EncryptedData {
+  List<int> _data;
+  List<int> _metadata;
+
+  List<int> get data => _data;
+  List<int> get metadata => _metadata;
+
+  EncryptedData._(this._data, this._metadata);
+
+  factory EncryptedData.from(data, metadata) => EncryptedData._(data, metadata);
+}

pubnub/lib/src/crypto/aesCbcCryptor.dart

@@ -0,0 +1,39 @@
+import 'package:encrypt/encrypt.dart' as crypto;
+import 'package:crypto/crypto.dart' show sha256;
+import 'dart:typed_data' show Uint8List;
+
+import 'package:pubnub/core.dart';
+class AesCbcCryptor implements ICryptor {
+  static const BLOCK_SIZE = 16;
+  CipherKey cipherKey;
+
+  AesCbcCryptor(this.cipherKey);
+  @override
+  List<int> decrypt(EncryptedData encryptedData) {
+    var encrypter =
+        crypto.Encrypter(crypto.AES(_getKey(), mode: crypto.AESMode.cbc));
+    return encrypter.decryptBytes(
+        crypto.Encrypted(Uint8List.fromList(encryptedData.data.toList())),
+        iv: crypto.IV(Uint8List.fromList(encryptedData.metadata.toList())));
+  }
+
+  @override
+  EncryptedData encrypt(List<int> input) {
+    var encrypter =
+        crypto.Encrypter(crypto.AES(_getKey(), mode: crypto.AESMode.cbc));
+    var iv = _getIv();
+    var data = encrypter.encryptBytes(input, iv: iv).bytes.toList();
+    return EncryptedData.from(data, iv.bytes.toList());
+  }
+
+  @override
+  String get identifier => 'ACRH';
+
+  crypto.IV _getIv() {
+    return crypto.IV.fromSecureRandom(BLOCK_SIZE);
+  }
+
+  crypto.Key _getKey() {
+    return crypto.Key.fromBase16(sha256.convert(cipherKey.data).toString());
+  }
+}

pubnub/test/unit/crypto/crypto_test.dart

@@ -1,4 +1,7 @@
+import 'dart:convert';
+
 import 'package:pubnub/core.dart';
+import 'package:pubnub/src/crypto/aesCbcCryptor.dart';
 import 'package:pubnub/src/crypto/crypto.dart';
 
 import 'package:test/test.dart';
@@ -28,8 +31,16 @@ void main() {
       var headerData = [80, 78, 69, 68, 1, 65, 67, 82, 72, 16];
       var expectedBytes = [...headerData, ...List<int>.filled(16, 0)];
 
-      CryptorHeaderV1? header = CryptorHeader.tryParse(encryptedDataWithHeader.codeUnits);
+      var header = CryptorHeader.tryParse(encryptedDataWithHeader.codeUnits);
       expect(header!.data, equals(expectedBytes));
     });
+
+    test('AesCbcCryptor should work as expected', () async {
+      var plainText = 'Hello there!';
+      var cryptor = AesCbcCryptor(CipherKey.fromUtf8('pubnubenigma'));
+      var encryptedData = cryptor.encrypt(plainText.codeUnits);
+      var decrypted = cryptor.decrypt(encryptedData);
+      expect(utf8.decode(decrypted), equals(plainText));
+    });
   });
 }