cleanup code

lib/encrypt/crypter.dart

@@ -1,7 +1,7 @@
+import 'dart:convert';
 import 'dart:math';
 import 'dart:typed_data';
 
-import '../utils.dart';
 import 'aes/aes_cbcpkcs7.dart';
 import 'kdf/kdf.dart';
 import 'kdf/sha256_kdf.dart';
@@ -11,16 +11,9 @@ import 'model/keyiv.dart';
 class NanoCrypt {
   /// Decrypts a value with a password using AES/CBC/PKCS7
   /// KDF is Sha256KDF if not specified
-  static Uint8List decrypt(dynamic value, String password, {KDF? kdf}) {
+  static Uint8List decrypt(Uint8List value, String password, {KDF? kdf}) {
     kdf = kdf ?? Sha256KDF();
-    Uint8List valBytes;
-    if (value is String) {
-      valBytes = hexToBytes(value);
-    } else if (value is Uint8List) {
-      valBytes = value;
-    } else {
-      throw Exception('Value should be a string or a byte array');
-    }
+    Uint8List valBytes = Uint8List.fromList(value);
 
     Uint8List salt = valBytes.sublist(8, 16);
     KeyIV key = kdf.deriveKey(password, salt: salt);
@@ -35,28 +28,20 @@ class NanoCrypt {
   /// KDF is Sha256KDF if not specified
   static Uint8List encrypt(dynamic value, String password, {KDF? kdf}) {
     kdf = kdf ?? Sha256KDF();
-    Uint8List valBytes;
-    if (value is String) {
-      valBytes = hexToBytes(value);
-    } else if (value is Uint8List) {
-      valBytes = value;
-    } else {
-      throw Exception('Seed should be a string or uint8list');
-    }
+    Uint8List valBytes = Uint8List.fromList(value);
 
     // Generate a random salt
     Uint8List salt = Uint8List(8);
     Random rng = Random.secure();
     for (int i = 0; i < 8; i++) {
-      salt[i] = rng.nextInt(255);
+      salt[i] = rng.nextInt(256);
     }
 
     KeyIV keyInfo = kdf.deriveKey(password, salt: salt);
 
     Uint8List seedEncrypted =
         AesCbcPkcs7.encrypt(valBytes, key: keyInfo.key, iv: keyInfo.iv);
 
-    return Uint8List.fromList(
-        stringToBytesUtf8("Salted__") + salt + seedEncrypted);
+    return Uint8List.fromList(utf8.encode('Salted__') + salt + seedEncrypted);
   }
 }

lib/encrypt/kdf/pbkdf2_kdf.dart

@@ -1,8 +1,8 @@
+import 'dart:convert';
 import 'dart:typed_data';
 
 import 'package:pointycastle/export.dart';
 
-import '../../utils.dart';
 import '../model/keyiv.dart';
 import 'kdf.dart';
 
@@ -12,7 +12,7 @@ class PBKDF2 extends KDF {
   /// Expects password to be a utf-8 string
   /// If salt is not provided, a random 8-byte one will be generated
   KeyIV deriveKey(String password, {Uint8List? salt}) {
-    Uint8List pwBytes = stringToBytesUtf8(password);
+    Uint8List pwBytes = utf8.encode(password);
     Uint8List saltBytes = salt == null ? Uint8List(1) : salt;
 
     // Use pbkdf2 from pointycastle

lib/encrypt/kdf/sha256_kdf.dart

@@ -1,6 +1,6 @@
+import 'dart:convert';
 import 'dart:typed_data';
 
-import '../../utils.dart';
 import '../model/keyiv.dart';
 import '../sha.dart';
 import 'kdf.dart';
@@ -12,7 +12,7 @@ import 'kdf.dart';
 class Sha256KDF extends KDF {
   /// Gets the key and iv
   KeyIV deriveKey(String password, {Uint8List? salt}) {
-    Uint8List pwBytes = stringToBytesUtf8(password);
+    Uint8List pwBytes = utf8.encode(password);
     Uint8List saltBytes = salt == null ? Uint8List(1) : salt;
 
     // Key = sha256 (password + salt);