diff --git a/packages/native_crypto/example/lib/pages/kdf_page.dart b/packages/native_crypto/example/lib/pages/kdf_page.dart
index b60a454..6eb9011 100644
--- a/packages/native_crypto/example/lib/pages/kdf_page.dart
+++ b/packages/native_crypto/example/lib/pages/kdf_page.dart
@@ -3,7 +3,7 @@
 // -----
 // File: kdf_page.dart
 // Created Date: 28/12/2021 13:40:34
-// Last Modified: 28/12/2021 15:14:12
+// Last Modified: 23/05/2022 22:49:06
 // -----
 // Copyright (c) 2021
 
@@ -50,7 +50,7 @@ class KdfPage extends ConsumerWidget {
     if (password.isEmpty) {
       pbkdf2Status.print('Password is empty');
     } else {
-      PBKDF2 _pbkdf2 = PBKDF2(32, 1000, algorithm: HashAlgorithm.sha512);
+      Pbkdf2 _pbkdf2 = Pbkdf2(32, 1000, algorithm: HashAlgorithm.sha512);
       SecretKey sk = await _pbkdf2.derive(password: password, salt: 'salt');
       state.setKey(sk);
       pbkdf2Status.print('Key successfully derived.');
@@ -59,14 +59,14 @@ class KdfPage extends ConsumerWidget {
     }
   }
 
-  Future<void> _hash(Hasher hasher) async {
+  Future<void> _hash(HashAlgorithm hasher) async {
     final message = _messageTextController.text.trim();
     if (message.isEmpty) {
       hashStatus.print('Message is empty');
     } else {
       Uint8List hash = await hasher.digest(message.toBytes());
       hashStatus.print(
-          'Message successfully hashed with ${hasher.algorithm} :${hash.toStr(to: Encoding.hex)}');
+          'Message successfully hashed with $hasher :${hash.toStr(to: Encoding.hex)}');
     }
   }
 
@@ -108,15 +108,15 @@ class KdfPage extends ConsumerWidget {
               mainAxisAlignment: MainAxisAlignment.spaceEvenly,
               children: [
                 Button(
-                  () => _hash(SHA256()),
+                  () => _hash(HashAlgorithm.sha256),
                   "SHA256",
                 ),
                 Button(
-                  () => _hash(SHA384()),
+                  () => _hash(HashAlgorithm.sha384),
                   "SHA384",
                 ),
                 Button(
-                  () => _hash(SHA512()),
+                  () => _hash(HashAlgorithm.sha512),
                   "SHA512",
                 ),
               ],
diff --git a/packages/native_crypto/lib/native_crypto.dart b/packages/native_crypto/lib/native_crypto.dart
index 12076c7..226381f 100644
--- a/packages/native_crypto/lib/native_crypto.dart
+++ b/packages/native_crypto/lib/native_crypto.dart
@@ -3,28 +3,27 @@
 // -----
 // File: native_crypto.dart
 // Created Date: 16/12/2021 16:28:00
-// Last Modified: 23/05/2022 21:43:54
+// Last Modified: 23/05/2022 23:09:10
 // -----
 // Copyright (c) 2021
 
-export 'src/byte_array.dart';
-export 'src/cipher.dart';
-export 'src/cipher_text.dart';
-export 'src/ciphers/aes.dart';
-export 'src/exceptions.dart';
-export 'src/hasher.dart';
-export 'src/hashers/sha256.dart';
-export 'src/hashers/sha384.dart';
-export 'src/hashers/sha512.dart';
-export 'src/kdf/pbkdf2.dart';
-export 'src/keyderivation.dart';
-export 'src/keys/secret_key.dart';
-export 'src/utils.dart';
+/// Fast and powerful cryptographic functions
+/// thanks to javax.crypto, CommonCrypto and CryptoKit.
+///
+/// Author: Hugo Pointcheval
+library native_crypto;
 
-const String version = '0.1.0';
-const String author = 'Hugo Pointcheval';
-const String website = 'https://hugo.pointcheval.fr/';
-const List<String> repositories = [
-  'https://github.com/hugo-pcl/native-crypto-flutter',
-  'https://git.pointcheval.fr/NativeCrypto/native-crypto-flutter'
-];
+export 'src/builders/builders.dart';
+export 'src/ciphers/ciphers.dart';
+export 'src/core/core.dart';
+export 'src/interfaces/interfaces.dart';
+export 'src/kdf/kdf.dart';
+export 'src/keys/keys.dart';
+// Utils
+export 'src/utils/cipher_algorithm.dart';
+export 'src/utils/convert.dart';
+export 'src/utils/hash_algorithm.dart';
+export 'src/utils/kdf_algorithm.dart';
+
+// ignore: constant_identifier_names
+const String AUTHOR = 'Hugo Pointcheval';
diff --git a/packages/native_crypto/lib/src/builders/aes_builder.dart b/packages/native_crypto/lib/src/builders/aes_builder.dart
index 898d79a..955849c 100644
--- a/packages/native_crypto/lib/src/builders/aes_builder.dart
+++ b/packages/native_crypto/lib/src/builders/aes_builder.dart
@@ -3,13 +3,13 @@
 // -----
 // File: aes_builder.dart
 // Created Date: 28/12/2021 12:03:11
-// Last Modified: 23/05/2022 21:46:33
+// Last Modified: 23/05/2022 23:05:19
 // -----
 // Copyright (c) 2021
 
-import 'package:native_crypto/src/builder.dart';
-import 'package:native_crypto/src/ciphers/aes.dart';
-import 'package:native_crypto/src/exceptions.dart';
+import 'package:native_crypto/src/ciphers/aes/aes.dart';
+import 'package:native_crypto/src/core/exceptions.dart';
+import 'package:native_crypto/src/interfaces/builder.dart';
 import 'package:native_crypto/src/keys/secret_key.dart';
 
 class AESBuilder implements Builder<AES> {
diff --git a/packages/native_crypto/lib/src/builders/builders.dart b/packages/native_crypto/lib/src/builders/builders.dart
new file mode 100644
index 0000000..e20a4a6
--- /dev/null
+++ b/packages/native_crypto/lib/src/builders/builders.dart
@@ -0,0 +1,10 @@
+// Author: Hugo Pointcheval
+// Email: git@pcl.ovh
+// -----
+// File: builders.dart
+// Created Date: 23/05/2022 22:56:03
+// Last Modified: 23/05/2022 22:56:12
+// -----
+// Copyright (c) 2022
+
+export 'aes_builder.dart';
diff --git a/packages/native_crypto/lib/src/ciphers/aes.dart b/packages/native_crypto/lib/src/ciphers/aes/aes.dart
similarity index 71%
rename from packages/native_crypto/lib/src/ciphers/aes.dart
rename to packages/native_crypto/lib/src/ciphers/aes/aes.dart
index 56c19a8..a1ae944 100644
--- a/packages/native_crypto/lib/src/ciphers/aes.dart
+++ b/packages/native_crypto/lib/src/ciphers/aes/aes.dart
@@ -3,39 +3,26 @@
 // -----
 // File: aes.dart
 // Created Date: 16/12/2021 16:28:00
-// Last Modified: 23/05/2022 21:47:08
+// Last Modified: 23/05/2022 23:06:05
 // -----
-// Copyright (c) 2021
+// Copyright (c) 2022
 
 import 'dart:typed_data';
 
-import 'package:native_crypto/src/cipher.dart';
-import 'package:native_crypto/src/cipher_text.dart';
-import 'package:native_crypto/src/exceptions.dart';
+import 'package:native_crypto/src/ciphers/aes/aes_key_size.dart';
+import 'package:native_crypto/src/ciphers/aes/aes_mode.dart';
+import 'package:native_crypto/src/ciphers/aes/aes_padding.dart';
+import 'package:native_crypto/src/core/cipher_text.dart';
+import 'package:native_crypto/src/core/cipher_text_list.dart';
+import 'package:native_crypto/src/core/exceptions.dart';
+import 'package:native_crypto/src/interfaces/cipher.dart';
 import 'package:native_crypto/src/keys/secret_key.dart';
 import 'package:native_crypto/src/platform.dart';
-import 'package:native_crypto/src/utils.dart';
+import 'package:native_crypto/src/utils/cipher_algorithm.dart';
 
-/// Defines the AES modes of operation.
-enum AESMode { gcm }
-
-/// Defines all available key sizes.
-enum AESKeySize { bits128, bits192, bits256 }
-
-/// Represents different paddings.
-enum AESPadding { none }
-
-extension AESKeySizeExtension on AESKeySize {
-  static final Map<AESKeySize, int> sizes = <AESKeySize, int>{
-    AESKeySize.bits128: 128,
-    AESKeySize.bits192: 192,
-    AESKeySize.bits256: 256,
-  };
-  static final List<int> supportedSizes = sizes.values.toList(growable: false);
-  int get length {
-    return sizes[this]!; // this is safe because `this` is listed in the enum
-  }
-}
+export 'package:native_crypto/src/ciphers/aes/aes_key_size.dart';
+export 'package:native_crypto/src/ciphers/aes/aes_mode.dart';
+export 'package:native_crypto/src/ciphers/aes/aes_padding.dart';
 
 class AES implements Cipher {
   final SecretKey key;
@@ -46,7 +33,7 @@ class AES implements Cipher {
   CipherAlgorithm get algorithm => CipherAlgorithm.aes;
 
   AES(this.key, this.mode, {this.padding = AESPadding.none}) {
-    if (!AESKeySizeExtension.supportedSizes.contains(key.bytes.length * 8)) {
+    if (!AESKeySize.supportedSizes.contains(key.bytes.length * 8)) {
       throw CipherInitException('Invalid key length!');
     }
 
@@ -67,7 +54,7 @@ class AES implements Cipher {
         final Uint8List d = await platform.decrypt(
               ct.bytes,
               key.bytes,
-              Utils.enumToStr(algorithm),
+              algorithm.name,
             ) ??
             Uint8List(0);
         decryptedData.add(d);
@@ -76,7 +63,7 @@ class AES implements Cipher {
       final Uint8List d = await platform.decrypt(
             cipherText.bytes,
             key.bytes,
-            Utils.enumToStr(algorithm),
+            algorithm.name,
           ) ??
           Uint8List(0);
       decryptedData.add(d);
@@ -102,7 +89,7 @@ class AES implements Cipher {
         final Uint8List c = await platform.encrypt(
               dataToEncrypt,
               key.bytes,
-              Utils.enumToStr(algorithm),
+              algorithm.name,
             ) ??
             Uint8List(0);
         cipherTextList.add(
@@ -115,7 +102,7 @@ class AES implements Cipher {
       }
     } else {
       final Uint8List c =
-          await platform.encrypt(data, key.bytes, Utils.enumToStr(algorithm)) ??
+          await platform.encrypt(data, key.bytes, algorithm.name) ??
               Uint8List(0);
 
       return CipherText(
diff --git a/packages/native_crypto/lib/src/ciphers/aes/aes_key_size.dart b/packages/native_crypto/lib/src/ciphers/aes/aes_key_size.dart
new file mode 100644
index 0000000..8018f0b
--- /dev/null
+++ b/packages/native_crypto/lib/src/ciphers/aes/aes_key_size.dart
@@ -0,0 +1,22 @@
+// Author: Hugo Pointcheval
+// Email: git@pcl.ovh
+// -----
+// File: aes_key_size.dart
+// Created Date: 23/05/2022 22:10:07
+// Last Modified: 23/05/2022 22:33:32
+// -----
+// Copyright (c) 2022
+
+/// Defines all available key sizes.
+enum AESKeySize {
+  bits128(128),
+  bits192(192),
+  bits256(256);
+
+  static final List<int> supportedSizes = [128, 192, 256];
+
+  final int bits;
+  int get bytes => bits ~/ 8;
+
+  const AESKeySize(this.bits);
+}
diff --git a/packages/native_crypto/lib/src/ciphers/aes/aes_mode.dart b/packages/native_crypto/lib/src/ciphers/aes/aes_mode.dart
new file mode 100644
index 0000000..554cdde
--- /dev/null
+++ b/packages/native_crypto/lib/src/ciphers/aes/aes_mode.dart
@@ -0,0 +1,11 @@
+// Author: Hugo Pointcheval
+// Email: git@pcl.ovh
+// -----
+// File: aes_mode.dart
+// Created Date: 23/05/2022 22:09:16
+// Last Modified: 23/05/2022 22:10:31
+// -----
+// Copyright (c) 2022
+
+/// Defines the AES modes of operation.
+enum AESMode { gcm }
diff --git a/packages/native_crypto/lib/src/ciphers/aes/aes_padding.dart b/packages/native_crypto/lib/src/ciphers/aes/aes_padding.dart
new file mode 100644
index 0000000..06e323b
--- /dev/null
+++ b/packages/native_crypto/lib/src/ciphers/aes/aes_padding.dart
@@ -0,0 +1,11 @@
+// Author: Hugo Pointcheval
+// Email: git@pcl.ovh
+// -----
+// File: aes_padding.dart
+// Created Date: 23/05/2022 22:10:17
+// Last Modified: 23/05/2022 22:13:28
+// -----
+// Copyright (c) 2022
+
+/// Represents different paddings.
+enum AESPadding { none }
diff --git a/packages/native_crypto/lib/src/ciphers/ciphers.dart b/packages/native_crypto/lib/src/ciphers/ciphers.dart
new file mode 100644
index 0000000..edae6a4
--- /dev/null
+++ b/packages/native_crypto/lib/src/ciphers/ciphers.dart
@@ -0,0 +1,10 @@
+// Author: Hugo Pointcheval
+// Email: git@pcl.ovh
+// -----
+// File: ciphers.dart
+// Created Date: 23/05/2022 22:56:30
+// Last Modified: 23/05/2022 22:56:47
+// -----
+// Copyright (c) 2022
+
+export 'aes/aes.dart';
diff --git a/packages/native_crypto/lib/src/cipher_text.dart b/packages/native_crypto/lib/src/core/cipher_text.dart
similarity index 72%
rename from packages/native_crypto/lib/src/cipher_text.dart
rename to packages/native_crypto/lib/src/core/cipher_text.dart
index bf79c27..cd840a3 100644
--- a/packages/native_crypto/lib/src/cipher_text.dart
+++ b/packages/native_crypto/lib/src/core/cipher_text.dart
@@ -3,13 +3,13 @@
 // -----
 // File: cipher_text.dart
 // Created Date: 16/12/2021 16:59:53
-// Last Modified: 23/05/2022 21:48:27
+// Last Modified: 23/05/2022 23:02:10
 // -----
 // Copyright (c) 2021
 
 import 'dart:typed_data';
 
-import 'package:native_crypto/src/byte_array.dart';
+import 'package:native_crypto/src/interfaces/byte_array.dart';
 
 class CipherText extends ByteArray {
   final int _ivLength;
@@ -43,18 +43,3 @@ class CipherText extends ByteArray {
   /// Gets the CipherText tag length.
   int get tagLength => _tagLength;
 }
-
-class CipherTextList extends CipherText {
-  static const int chunkSize = 33554432;
-  final List<CipherText> _list;
-
-  CipherTextList()
-      : _list = [],
-        super(Uint8List(0), Uint8List(0), Uint8List(0));
-
-  void add(CipherText cipherText) {
-    _list.add(cipherText);
-  }
-
-  List<CipherText> get list => _list;
-}
diff --git a/packages/native_crypto/lib/src/core/cipher_text_list.dart b/packages/native_crypto/lib/src/core/cipher_text_list.dart
new file mode 100644
index 0000000..9d16211
--- /dev/null
+++ b/packages/native_crypto/lib/src/core/cipher_text_list.dart
@@ -0,0 +1,27 @@
+// Author: Hugo Pointcheval
+// Email: git@pcl.ovh
+// -----
+// File: cipher_text_list.dart
+// Created Date: 23/05/2022 22:59:02
+// Last Modified: 23/05/2022 23:05:02
+// -----
+// Copyright (c) 2022
+
+import 'dart:typed_data';
+
+import 'package:native_crypto/src/core/cipher_text.dart';
+
+class CipherTextList extends CipherText {
+  static const int chunkSize = 33554432;
+  final List<CipherText> _list;
+
+  CipherTextList()
+      : _list = [],
+        super(Uint8List(0), Uint8List(0), Uint8List(0));
+
+  void add(CipherText cipherText) {
+    _list.add(cipherText);
+  }
+
+  List<CipherText> get list => _list;
+}
diff --git a/packages/native_crypto/lib/src/core/core.dart b/packages/native_crypto/lib/src/core/core.dart
new file mode 100644
index 0000000..97597ac
--- /dev/null
+++ b/packages/native_crypto/lib/src/core/core.dart
@@ -0,0 +1,12 @@
+// Author: Hugo Pointcheval
+// Email: git@pcl.ovh
+// -----
+// File: core.dart
+// Created Date: 23/05/2022 23:05:26
+// Last Modified: 23/05/2022 23:05:30
+// -----
+// Copyright (c) 2022
+
+export 'cipher_text.dart';
+export 'cipher_text_list.dart';
+export 'exceptions.dart';
diff --git a/packages/native_crypto/lib/src/exceptions.dart b/packages/native_crypto/lib/src/core/exceptions.dart
similarity index 62%
rename from packages/native_crypto/lib/src/exceptions.dart
rename to packages/native_crypto/lib/src/core/exceptions.dart
index 10af511..96c21d0 100644
--- a/packages/native_crypto/lib/src/exceptions.dart
+++ b/packages/native_crypto/lib/src/core/exceptions.dart
@@ -3,7 +3,7 @@
 // -----
 // File: exceptions.dart
 // Created Date: 16/12/2021 16:28:00
-// Last Modified: 23/05/2022 21:51:55
+// Last Modified: 23/05/2022 22:30:27
 // -----
 // Copyright (c) 2021
 
@@ -13,29 +13,29 @@ class NativeCryptoException implements Exception {
 }
 
 class UtilsException extends NativeCryptoException {
-  UtilsException(String message) : super(message);
+  UtilsException(super.message);
 }
 
 class KeyException extends NativeCryptoException {
-  KeyException(String message) : super(message);
+  KeyException(super.message);
 }
 
 class KeyDerivationException extends NativeCryptoException {
-  KeyDerivationException(String message) : super(message);
+  KeyDerivationException(super.message);
 }
 
 class CipherInitException extends NativeCryptoException {
-  CipherInitException(String message) : super(message);
+  CipherInitException(super.message);
 }
 
 class EncryptionException extends NativeCryptoException {
-  EncryptionException(String message) : super(message);
+  EncryptionException(super.message);
 }
 
 class DecryptionException extends NativeCryptoException {
-  DecryptionException(String message) : super(message);
+  DecryptionException(super.message);
 }
 
 class NotImplementedException extends NativeCryptoException {
-  NotImplementedException(String message) : super(message);
+  NotImplementedException(super.message);
 }
diff --git a/packages/native_crypto/lib/src/hasher.dart b/packages/native_crypto/lib/src/hasher.dart
deleted file mode 100644
index d81b7cc..0000000
--- a/packages/native_crypto/lib/src/hasher.dart
+++ /dev/null
@@ -1,29 +0,0 @@
-// Author: Hugo Pointcheval
-// Email: git@pcl.ovh
-// -----
-// File: hasher.dart
-// Created Date: 16/12/2021 16:28:00
-// Last Modified: 27/12/2021 22:06:29
-// -----
-// Copyright (c) 2021
-
-import 'dart:typed_data';
-
-import 'platform.dart';
-import 'utils.dart';
-
-enum HashAlgorithm { sha256, sha384, sha512 }
-
-abstract class Hasher {
-  /// Returns the standard algorithm name for this digest
-  HashAlgorithm get algorithm;
-
-  /// Hashes a message
-  Future<Uint8List> digest(Uint8List data) async {
-    Uint8List hash =
-        (await platform.digest(data, Utils.enumToStr(algorithm))) ??
-            Uint8List(0);
-
-    return hash;
-  }
-}
diff --git a/packages/native_crypto/lib/src/hashers/sha256.dart b/packages/native_crypto/lib/src/hashers/sha256.dart
deleted file mode 100644
index 8f88189..0000000
--- a/packages/native_crypto/lib/src/hashers/sha256.dart
+++ /dev/null
@@ -1,15 +0,0 @@
-// Author: Hugo Pointcheval
-// Email: git@pcl.ovh
-// -----
-// File: sha256.dart
-// Created Date: 17/12/2021 11:31:20
-// Last Modified: 23/05/2022 21:47:23
-// -----
-// Copyright (c) 2021
-
-import 'package:native_crypto/src/hasher.dart';
-
-class SHA256 extends Hasher {
-  @override
-  HashAlgorithm get algorithm => HashAlgorithm.sha256;
-}
diff --git a/packages/native_crypto/lib/src/hashers/sha384.dart b/packages/native_crypto/lib/src/hashers/sha384.dart
deleted file mode 100644
index f7630eb..0000000
--- a/packages/native_crypto/lib/src/hashers/sha384.dart
+++ /dev/null
@@ -1,15 +0,0 @@
-// Author: Hugo Pointcheval
-// Email: git@pcl.ovh
-// -----
-// File: sha384.dart
-// Created Date: 17/12/2021 11:31:53
-// Last Modified: 23/05/2022 21:47:28
-// -----
-// Copyright (c) 2021
-
-import 'package:native_crypto/src/hasher.dart';
-
-class SHA384 extends Hasher {
-  @override
-  HashAlgorithm get algorithm => HashAlgorithm.sha384;
-}
diff --git a/packages/native_crypto/lib/src/hashers/sha512.dart b/packages/native_crypto/lib/src/hashers/sha512.dart
deleted file mode 100644
index 881887c..0000000
--- a/packages/native_crypto/lib/src/hashers/sha512.dart
+++ /dev/null
@@ -1,15 +0,0 @@
-// Author: Hugo Pointcheval
-// Email: git@pcl.ovh
-// -----
-// File: sha512.dart
-// Created Date: 17/12/2021 11:32:14
-// Last Modified: 23/05/2022 21:47:35
-// -----
-// Copyright (c) 2021
-
-import 'package:native_crypto/src/hasher.dart';
-
-class SHA512 extends Hasher {
-  @override
-  HashAlgorithm get algorithm => HashAlgorithm.sha512;
-}
diff --git a/packages/native_crypto/lib/src/builder.dart b/packages/native_crypto/lib/src/interfaces/builder.dart
similarity index 71%
rename from packages/native_crypto/lib/src/builder.dart
rename to packages/native_crypto/lib/src/interfaces/builder.dart
index 4817768..a1b39aa 100644
--- a/packages/native_crypto/lib/src/builder.dart
+++ b/packages/native_crypto/lib/src/interfaces/builder.dart
@@ -3,10 +3,12 @@
 // -----
 // File: builder.dart
 // Created Date: 28/12/2021 12:02:34
-// Last Modified: 28/12/2021 12:32:12
+// Last Modified: 23/05/2022 22:38:44
 // -----
 // Copyright (c) 2021
 
+// ignore_for_file: one_member_abstracts
+
 abstract class Builder<T> {
   Future<T> build();
 }
diff --git a/packages/native_crypto/lib/src/byte_array.dart b/packages/native_crypto/lib/src/interfaces/byte_array.dart
similarity index 84%
rename from packages/native_crypto/lib/src/byte_array.dart
rename to packages/native_crypto/lib/src/interfaces/byte_array.dart
index 18c2fcf..23d3ba4 100644
--- a/packages/native_crypto/lib/src/byte_array.dart
+++ b/packages/native_crypto/lib/src/interfaces/byte_array.dart
@@ -3,23 +3,25 @@
 // -----
 // File: byte_array.dart
 // Created Date: 16/12/2021 17:54:16
-// Last Modified: 23/05/2022 21:44:38
+// Last Modified: 23/05/2022 23:07:03
 // -----
 // Copyright (c) 2021
 
 import 'dart:convert' as convert;
 import 'dart:typed_data';
 
-import 'package:native_crypto/src/utils.dart';
+import 'package:flutter/foundation.dart';
+import 'package:native_crypto/src/utils/convert.dart';
 
-class ByteArray {
-  Uint8List _bytes;
+@immutable
+abstract class ByteArray {
+  final Uint8List _bytes;
 
-  ByteArray(this._bytes);
+  const ByteArray(this._bytes);
 
   /// Creates an ByteArray object from a hexdecimal string.
   ByteArray.fromBase16(String encoded)
-      : _bytes = Utils.decodeHexString(encoded);
+      : _bytes = Convert.decodeHexString(encoded);
 
   /// Creates an ByteArray object from a Base64 string.
   ByteArray.fromBase64(String encoded)
@@ -36,9 +38,6 @@ class ByteArray {
   // ignore: unnecessary_getters_setters
   Uint8List get bytes => _bytes;
 
-  /// Sets the ByteArray bytes.
-  set bytes(Uint8List value) => _bytes = value;
-
   /// Gets the ByteArray bytes as a Hexadecimal representation.
   String get base16 =>
       _bytes.map((byte) => byte.toRadixString(16).padLeft(2, '0')).join();
diff --git a/packages/native_crypto/lib/src/cipher.dart b/packages/native_crypto/lib/src/interfaces/cipher.dart
similarity index 83%
rename from packages/native_crypto/lib/src/cipher.dart
rename to packages/native_crypto/lib/src/interfaces/cipher.dart
index 9d5dee8..df8296a 100644
--- a/packages/native_crypto/lib/src/cipher.dart
+++ b/packages/native_crypto/lib/src/interfaces/cipher.dart
@@ -3,16 +3,14 @@
 // -----
 // File: cipher.dart
 // Created Date: 16/12/2021 16:28:00
-// Last Modified: 28/12/2021 12:25:38
+// Last Modified: 23/05/2022 23:06:20
 // -----
 // Copyright (c) 2021
 
 import 'dart:typed_data';
 
-import 'cipher_text.dart';
-
-/// Represents different cipher algorithms
-enum CipherAlgorithm { aes, rsa }
+import 'package:native_crypto/src/core/cipher_text.dart';
+import 'package:native_crypto/src/utils/cipher_algorithm.dart';
 
 /// Represents a cipher.
 ///
diff --git a/packages/native_crypto/lib/src/interfaces/interfaces.dart b/packages/native_crypto/lib/src/interfaces/interfaces.dart
new file mode 100644
index 0000000..3ff3855
--- /dev/null
+++ b/packages/native_crypto/lib/src/interfaces/interfaces.dart
@@ -0,0 +1,14 @@
+// Author: Hugo Pointcheval
+// Email: git@pcl.ovh
+// -----
+// File: interfaces.dart
+// Created Date: 23/05/2022 23:03:47
+// Last Modified: 23/05/2022 23:10:15
+// -----
+// Copyright (c) 2022
+
+export 'builder.dart';
+export 'byte_array.dart';
+export 'cipher.dart';
+// export 'key.dart';
+export 'keyderivation.dart';
diff --git a/packages/native_crypto/lib/src/interfaces/key.dart b/packages/native_crypto/lib/src/interfaces/key.dart
new file mode 100644
index 0000000..3c99f0c
--- /dev/null
+++ b/packages/native_crypto/lib/src/interfaces/key.dart
@@ -0,0 +1,18 @@
+// Author: Hugo Pointcheval
+// Email: git@pcl.ovh
+// -----
+// File: key.dart
+// Created Date: 16/12/2021 16:28:00
+// Last Modified: 23/05/2022 23:02:10
+// -----
+// Copyright (c) 2021
+
+import 'package:native_crypto/src/interfaces/byte_array.dart';
+
+/// A class representing a key.
+abstract class Key extends ByteArray {
+  const Key(super.bytes);
+  Key.fromBase16(super.encoded) : super.fromBase16();
+  Key.fromBase64(super.encoded) : super.fromBase64();
+  Key.fromUtf8(super.input) : super.fromUtf8();
+}
diff --git a/packages/native_crypto/lib/src/keyderivation.dart b/packages/native_crypto/lib/src/interfaces/keyderivation.dart
similarity index 70%
rename from packages/native_crypto/lib/src/keyderivation.dart
rename to packages/native_crypto/lib/src/interfaces/keyderivation.dart
index b3cba30..cddb1bc 100644
--- a/packages/native_crypto/lib/src/keyderivation.dart
+++ b/packages/native_crypto/lib/src/interfaces/keyderivation.dart
@@ -3,13 +3,12 @@
 // -----
 // File: kdf.dart
 // Created Date: 18/12/2021 11:56:43
-// Last Modified: 28/12/2021 13:38:02
+// Last Modified: 23/05/2022 22:37:04
 // -----
 // Copyright (c) 2021
 
-import './keys/secret_key.dart';
-
-enum KdfAlgorithm { pbkdf2 }
+import 'package:native_crypto/src/keys/secret_key.dart';
+import 'package:native_crypto/src/utils/kdf_algorithm.dart';
 
 /// Represents a Key Derivation Function
 abstract class KeyDerivation {
diff --git a/packages/native_crypto/lib/src/kdf/kdf.dart b/packages/native_crypto/lib/src/kdf/kdf.dart
new file mode 100644
index 0000000..cb7d609
--- /dev/null
+++ b/packages/native_crypto/lib/src/kdf/kdf.dart
@@ -0,0 +1,10 @@
+// Author: Hugo Pointcheval
+// Email: git@pcl.ovh
+// -----
+// File: kdf.dart
+// Created Date: 23/05/2022 22:57:11
+// Last Modified: 23/05/2022 23:04:15
+// -----
+// Copyright (c) 2022
+
+export 'pbkdf2.dart';
diff --git a/packages/native_crypto/lib/src/kdf/pbkdf2.dart b/packages/native_crypto/lib/src/kdf/pbkdf2.dart
index 8d8aa55..04672bd 100644
--- a/packages/native_crypto/lib/src/kdf/pbkdf2.dart
+++ b/packages/native_crypto/lib/src/kdf/pbkdf2.dart
@@ -3,20 +3,20 @@
 // -----
 // File: pbkdf2.dart
 // Created Date: 17/12/2021 14:50:42
-// Last Modified: 23/05/2022 21:47:43
+// Last Modified: 23/05/2022 23:07:19
 // -----
 // Copyright (c) 2021
 
 import 'dart:typed_data';
 
-import 'package:native_crypto/src/exceptions.dart';
-import 'package:native_crypto/src/hasher.dart';
-import 'package:native_crypto/src/keyderivation.dart';
+import 'package:native_crypto/src/core/exceptions.dart';
+import 'package:native_crypto/src/interfaces/keyderivation.dart';
 import 'package:native_crypto/src/keys/secret_key.dart';
 import 'package:native_crypto/src/platform.dart';
-import 'package:native_crypto/src/utils.dart';
+import 'package:native_crypto/src/utils/hash_algorithm.dart';
+import 'package:native_crypto/src/utils/kdf_algorithm.dart';
 
-class PBKDF2 extends KeyDerivation {
+class Pbkdf2 extends KeyDerivation {
   final int _keyBytesCount;
   final int _iterations;
   final HashAlgorithm _hash;
@@ -24,7 +24,7 @@ class PBKDF2 extends KeyDerivation {
   @override
   KdfAlgorithm get algorithm => KdfAlgorithm.pbkdf2;
 
-  PBKDF2(
+  Pbkdf2(
     int keyBytesCount,
     int iterations, {
     HashAlgorithm algorithm = HashAlgorithm.sha256,
@@ -43,7 +43,7 @@ class PBKDF2 extends KeyDerivation {
           salt,
           _keyBytesCount,
           _iterations,
-          Utils.enumToStr(_hash),
+          _hash.name,
         )) ??
         Uint8List(0);
 
diff --git a/packages/native_crypto/lib/src/key.dart b/packages/native_crypto/lib/src/key.dart
deleted file mode 100644
index ed7d98c..0000000
--- a/packages/native_crypto/lib/src/key.dart
+++ /dev/null
@@ -1,20 +0,0 @@
-// Author: Hugo Pointcheval
-// Email: git@pcl.ovh
-// -----
-// File: key.dart
-// Created Date: 16/12/2021 16:28:00
-// Last Modified: 28/12/2021 13:37:50
-// -----
-// Copyright (c) 2021
-
-import 'dart:typed_data';
-
-import 'byte_array.dart';
-
-/// A class representing a key.
-class Key extends ByteArray {
-  Key(Uint8List bytes) : super(bytes);
-  Key.fromBase16(String encoded) : super.fromBase16(encoded);
-  Key.fromBase64(String encoded) : super.fromBase64(encoded);
-  Key.fromUtf8(String input) : super.fromUtf8(input);
-}
diff --git a/packages/native_crypto/lib/src/keys/keys.dart b/packages/native_crypto/lib/src/keys/keys.dart
new file mode 100644
index 0000000..912bb39
--- /dev/null
+++ b/packages/native_crypto/lib/src/keys/keys.dart
@@ -0,0 +1,10 @@
+// Author: Hugo Pointcheval
+// Email: git@pcl.ovh
+// -----
+// File: keys.dart
+// Created Date: 23/05/2022 23:04:04
+// Last Modified: 23/05/2022 23:04:07
+// -----
+// Copyright (c) 2022
+
+export 'secret_key.dart';
diff --git a/packages/native_crypto/lib/src/keys/secret_key.dart b/packages/native_crypto/lib/src/keys/secret_key.dart
index 7fbdd5f..98a1097 100644
--- a/packages/native_crypto/lib/src/keys/secret_key.dart
+++ b/packages/native_crypto/lib/src/keys/secret_key.dart
@@ -3,26 +3,25 @@
 // -----
 // File: secret_key.dart
 // Created Date: 28/12/2021 13:36:54
-// Last Modified: 23/05/2022 21:52:05
+// Last Modified: 23/05/2022 23:07:28
 // -----
 // Copyright (c) 2021
 
 import 'dart:typed_data';
 
 import 'package:flutter/services.dart';
-
-import 'package:native_crypto/src/exceptions.dart';
-import 'package:native_crypto/src/key.dart';
+import 'package:native_crypto/src/core/exceptions.dart';
+import 'package:native_crypto/src/interfaces/key.dart';
 import 'package:native_crypto/src/platform.dart';
 
 /// A class representing a secret key.
 /// A secret key is a key that is not accessible by anyone else.
 /// It is used to encrypt and decrypt data.
 class SecretKey extends Key {
-  SecretKey(Uint8List bytes) : super(bytes);
-  SecretKey.fromBase16(String encoded) : super.fromBase16(encoded);
-  SecretKey.fromBase64(String encoded) : super.fromBase64(encoded);
-  SecretKey.fromUtf8(String input) : super.fromUtf8(input);
+  const SecretKey(super.bytes);
+  SecretKey.fromBase16(super.encoded) : super.fromBase16();
+  SecretKey.fromBase64(super.encoded) : super.fromBase64();
+  SecretKey.fromUtf8(super.input) : super.fromUtf8();
 
   static Future<SecretKey> fromSecureRandom(int bitsCount) async {
     try {
diff --git a/packages/native_crypto/lib/src/utils.dart b/packages/native_crypto/lib/src/utils.dart
deleted file mode 100644
index 67a6411..0000000
--- a/packages/native_crypto/lib/src/utils.dart
+++ /dev/null
@@ -1,92 +0,0 @@
-// Author: Hugo Pointcheval
-// Email: git@pcl.ovh
-// -----
-// File: utils.dart
-// Created Date: 16/12/2021 16:28:00
-// Last Modified: 23/05/2022 21:45:56
-// -----
-// Copyright (c) 2021
-
-import 'dart:typed_data';
-
-import 'package:native_crypto/src/cipher.dart';
-import 'package:native_crypto/src/exceptions.dart';
-import 'package:native_crypto/src/hasher.dart';
-import 'package:native_crypto/src/keyderivation.dart';
-
-class Utils {
-  /// Returns enum value to string, without the enum name
-  static String enumToStr(dynamic enumValue) {
-    return enumValue.toString().split('.').last;
-  }
-
-  /// Returns enum list as string list
-  static List<String> enumToList<T>(List<T> enumValues) {
-    final List<String> _res = [];
-    for (final T enumValue in enumValues) {
-      _res.add(enumToStr(enumValue));
-    }
-
-    return _res;
-  }
-
-  /// Returns enum from string
-  static T strToEnum<T>(String str, List<T> enumValues) {
-    for (final T enumValue in enumValues) {
-      if (enumToStr(enumValue) == str) {
-        return enumValue;
-      }
-    }
-    throw UtilsException('Invalid enum value: $str');
-  }
-
-  /// Returns [HashAlgorithm] from his name.
-  static HashAlgorithm getHashAlgorithm(String algorithm) {
-    return strToEnum<HashAlgorithm>(
-      algorithm.toLowerCase(),
-      HashAlgorithm.values,
-    );
-  }
-
-  /// Returns all available [HashAlgorithm] as String list
-  static List<String> getAvailableHashAlgorithms() {
-    return enumToList<HashAlgorithm>(HashAlgorithm.values);
-  }
-
-  /// Returns [KdfAlgorithm] from his name.
-  static KdfAlgorithm getKdfAlgorithm(String algorithm) {
-    return strToEnum<KdfAlgorithm>(
-      algorithm.toLowerCase(),
-      KdfAlgorithm.values,
-    );
-  }
-
-  /// Returns all available [KdfAlgorithm] as String list
-  static List<String> getAvailableKdfAlgorithms() {
-    return enumToList<KdfAlgorithm>(KdfAlgorithm.values);
-  }
-
-  /// Returns [CipherAlgorithm] from his name.
-  static CipherAlgorithm getCipherAlgorithm(String algorithm) {
-    return strToEnum<CipherAlgorithm>(
-      algorithm.toLowerCase(),
-      CipherAlgorithm.values,
-    );
-  }
-
-  /// Returns all available [CipherAlgorithm] as String list
-  static List<String> getAvailableCipherAlgorithms() {
-    return enumToList<CipherAlgorithm>(CipherAlgorithm.values);
-  }
-
-  static Uint8List decodeHexString(String input) {
-    assert(input.length.isEven, 'Input needs to be an even length.');
-
-    return Uint8List.fromList(
-      List.generate(
-        input.length ~/ 2,
-        (i) => int.parse(input.substring(i * 2, (i * 2) + 2), radix: 16),
-      ).toList(),
-    );
-  }
-}
diff --git a/packages/native_crypto/lib/src/utils/cipher_algorithm.dart b/packages/native_crypto/lib/src/utils/cipher_algorithm.dart
new file mode 100644
index 0000000..5498bbc
--- /dev/null
+++ b/packages/native_crypto/lib/src/utils/cipher_algorithm.dart
@@ -0,0 +1,11 @@
+// Author: Hugo Pointcheval
+// Email: git@pcl.ovh
+// -----
+// File: cipher_algorithm.dart
+// Created Date: 23/05/2022 22:07:54
+// Last Modified: 23/05/2022 22:33:56
+// -----
+// Copyright (c) 2022
+
+/// Represents different cipher algorithms
+enum CipherAlgorithm { aes, rsa }
diff --git a/packages/native_crypto/lib/src/utils/convert.dart b/packages/native_crypto/lib/src/utils/convert.dart
new file mode 100644
index 0000000..f68bb78
--- /dev/null
+++ b/packages/native_crypto/lib/src/utils/convert.dart
@@ -0,0 +1,23 @@
+// Author: Hugo Pointcheval
+// Email: git@pcl.ovh
+// -----
+// File: convert.dart
+// Created Date: 16/12/2021 16:28:00
+// Last Modified: 23/05/2022 22:39:19
+// -----
+// Copyright (c) 2021
+
+import 'dart:typed_data';
+
+abstract class Convert {
+  static Uint8List decodeHexString(String input) {
+    assert(input.length.isEven, 'Input needs to be an even length.');
+
+    return Uint8List.fromList(
+      List.generate(
+        input.length ~/ 2,
+        (i) => int.parse(input.substring(i * 2, (i * 2) + 2), radix: 16),
+      ).toList(),
+    );
+  }
+}
diff --git a/packages/native_crypto/lib/src/utils/hash_algorithm.dart b/packages/native_crypto/lib/src/utils/hash_algorithm.dart
new file mode 100644
index 0000000..4e914cd
--- /dev/null
+++ b/packages/native_crypto/lib/src/utils/hash_algorithm.dart
@@ -0,0 +1,25 @@
+// Author: Hugo Pointcheval
+// Email: git@pcl.ovh
+// -----
+// File: hash_algorithm.dart
+// Created Date: 23/05/2022 22:01:59
+// Last Modified: 23/05/2022 22:47:08
+// -----
+// Copyright (c) 2022
+
+import 'dart:typed_data';
+
+import 'package:native_crypto/src/platform.dart';
+
+enum HashAlgorithm {
+  sha256,
+  sha384,
+  sha512;
+  
+  /// Hashes a message
+  Future<Uint8List> digest(Uint8List data) async {
+    final Uint8List hash = (await platform.digest(data, name)) ?? Uint8List(0);
+
+    return hash;
+  }
+}
diff --git a/packages/native_crypto/lib/src/utils/kdf_algorithm.dart b/packages/native_crypto/lib/src/utils/kdf_algorithm.dart
new file mode 100644
index 0000000..58ff68a
--- /dev/null
+++ b/packages/native_crypto/lib/src/utils/kdf_algorithm.dart
@@ -0,0 +1,10 @@
+// Author: Hugo Pointcheval
+// Email: git@pcl.ovh
+// -----
+// File: kdf_algorithm.dart
+// Created Date: 23/05/2022 22:36:24
+// Last Modified: 23/05/2022 22:36:36
+// -----
+// Copyright (c) 2022
+
+enum KdfAlgorithm { pbkdf2 }
diff --git a/packages/native_crypto/pubspec.yaml b/packages/native_crypto/pubspec.yaml
index 2f2648e..39e6c48 100644
--- a/packages/native_crypto/pubspec.yaml
+++ b/packages/native_crypto/pubspec.yaml
@@ -5,7 +5,7 @@ version: 0.1.0
 publish_to: 'none'
 
 environment:
-  sdk: ">=2.15.0 <3.0.0"
+  sdk: ">=2.17.0 <3.0.0"
   flutter: ">=2.5.0"
 
 dependencies: