feat: Bring over the cryptography API from moxplatform

example/lib/main.dart

@@ -1,3 +1,5 @@
+import 'dart:io';
+import 'dart:typed_data';
 import 'package:flutter/material.dart';
 import 'package:moxxy_native/moxxy_native.dart';
 
@@ -5,9 +7,16 @@ void main() {
   runApp(const MyApp());
 }
 
-class MyApp extends StatelessWidget {
+class MyApp extends StatefulWidget {
   const MyApp({super.key});
 
+  @override
+  MyAppState createState() => MyAppState();
+}
+
+class MyAppState extends State<MyApp> {
+  String? imagePath;
+
   @override
   Widget build(BuildContext context) {
     return MaterialApp(
@@ -44,6 +53,48 @@ class MyApp extends StatelessWidget {
               },
               child: const Text('Generic multi-picker'),
             ),
+            TextButton(
+              onPressed: () async {
+                final result = await MoxxyPickerApi().pickFiles(FilePickerType.image, false);
+                if (result.isEmpty) return;
+
+                final encDest = result.first! + '.enc';
+                final decDest = result.first! + '.dec';
+                final encResult = await MoxxyCryptographyApi().encryptFile(
+                  result.first!,
+                  encDest,
+                  Uint8List.fromList(List.filled(32, 1)),
+                  Uint8List.fromList(List.filled(16, 2)),
+                  CipherAlgorithm.aes256CbcPkcs7,
+                  'SHA-256',
+                );
+                if (encResult == null) {
+                  print('Failed to encrypt file');
+                  return;
+                }
+
+                final decResult = await MoxxyCryptographyApi().decryptFile(
+                  encDest,
+                  decDest,
+                  Uint8List.fromList(List.filled(32, 1)),
+                  Uint8List.fromList(List.filled(16, 2)),
+                  CipherAlgorithm.aes256CbcPkcs7,
+                  'SHA-256',
+                );
+                if (decResult == null) {
+                  print('Failed to decrypt file');
+                  return;
+                }
+
+                setState(() {
+                  imagePath = decDest;
+                });
+              },
+              child: Text('Test cryptography'),
+            ),
+
+            if (imagePath != null)
+              Image.file(File(imagePath!)),
           ],
         ),
       ),