diff --git a/bin/_argon2.dart b/bin/_argon2.dart
new file mode 100644
index 0000000..f49c070
--- /dev/null
+++ b/bin/_argon2.dart
@@ -0,0 +1,50 @@
+// ignore_for_file: non_constant_identifier_names
+
+//typedef HashStuff = Pointer<Utf8> Function(Pointer<Utf8> str);
+import 'dart:ffi';
+import 'dart:io';
+
+import 'package:ffi/ffi.dart';
+import 'package:kdbx/kdbx.dart';
+
+// TODO: This should be somehow combined with the test variant
+//       which also loads the requierd dylib/so files.
+
+typedef Argon2HashNative = Pointer<Utf8> Function(
+  Pointer<Uint8> key,
+  IntPtr keyLen,
+  Pointer<Uint8> salt,
+  Uint64 saltlen,
+  Uint32 m_cost, // memory cost
+  Uint32 t_cost, // time cost (number iterations)
+  Uint32 parallelism,
+  IntPtr hashlen,
+  Uint8 type,
+  Uint32 version,
+);
+typedef Argon2Hash = Pointer<Utf8> Function(
+  Pointer<Uint8> key,
+  int keyLen,
+  Pointer<Uint8> salt,
+  int saltlen,
+  int m_cost, // memory cost
+  int t_cost, // time cost (number iterations)
+  int parallelism,
+  int hashlen,
+  int type,
+  int version,
+);
+
+class Argon2Test extends Argon2Base {
+  Argon2Test() {
+    final argon2lib = Platform.isMacOS
+        ? DynamicLibrary.open('libargon2_ffi.dylib')
+        : DynamicLibrary.open('./libargon2_ffi.so');
+    argon2hash = argon2lib
+        .lookup<NativeFunction<Argon2HashNative>>('hp_argon2_hash')
+        .asFunction();
+  }
+
+  @override
+  Argon2Hash argon2hash;
+}
diff --git a/bin/kdbx.dart b/bin/kdbx.dart
index 9811553..eb49717 100644
--- a/bin/kdbx.dart
+++ b/bin/kdbx.dart
@@ -11,6 +11,8 @@ import 'package:logging/logging.dart';
 import 'package:logging_appenders/logging_appenders.dart';
 import 'package:prompts/prompts.dart' as prompts;
 
+import '_argon2.dart';
+
 final _logger = Logger('kdbx');
 
 void main(List<String> arguments) {
@@ -63,6 +65,12 @@ abstract class KdbxFileCommand extends Command<void> {
       help: 'Input kdbx file',
       valueHelp: 'foo.kdbx',
     );
+    argParser.addOption(
+      'password',
+      abbr: 'p',
+      help: 'password',
+      valueHelp: 'asdf',
+    );
   }
 
   @override
@@ -72,9 +80,10 @@ abstract class KdbxFileCommand extends Command<void> {
       usageException('Required argument: --input');
     }
     final bytes = await File(inputFile).readAsBytes();
-    final password = prompts.get('Password for $inputFile',
-        conceal: true, validate: (str) => str.isNotEmpty);
-    final file = await KdbxFormat(null)
+    final password = argResults['password'] as String ??
+        prompts.get('Password for $inputFile',
+            conceal: true, validate: (str) => str.isNotEmpty);
+    final file = await KdbxFormat(Argon2Test())
         .read(bytes, Credentials(ProtectedValue.fromString(password)));
     return runWithFile(file);
   }
diff --git a/lib/src/kdbx_format.dart b/lib/src/kdbx_format.dart
index a5c70f9..ff0d1af 100644
--- a/lib/src/kdbx_format.dart
+++ b/lib/src/kdbx_format.dart
@@ -632,6 +632,7 @@ class KdbxFormat {
   Uint8List _decryptContentV4(
       KdbxHeader header, Uint8List cipherKey, Uint8List encryptedPayload) {
     final encryptionIv = header.fields[HeaderFields.EncryptionIV].bytes;
+
     final decryptCipher = CBCBlockCipher(AESFastEngine());
     decryptCipher.init(
         false, ParametersWithIV(KeyParameter(cipherKey), encryptionIv));