Add example of AES api usage

example/lib/main.dart

@@ -1,11 +1,11 @@
 // Copyright (c) 2020
 // Author: Hugo Pointcheval
+import 'dart:developer';
 import 'dart:typed_data';
 
-import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 
-import 'package:native_crypto/native_crypto.dart';
+import 'package:native_crypto/symmetrical_crypto.dart';
 
 void main() => runApp(MyApp());
 
@@ -17,19 +17,20 @@ class MyApp extends StatefulWidget {
 class _MyAppState extends State<MyApp> {
   final textController = TextEditingController();
   String _output = 'none';
+  String _bench;
 
-  Uint8List aeskey;
+  AES aes = AES();
-  List<Uint8List> encryptedPayload;
+  Encrypted encrypted = Encrypted();
   Uint8List decryptedPayload;
 
-  void generateKey() async {
+  void _generateKey() async {
-    aeskey = await NativeCrypto().symKeygen();
+    await aes.init(KeySize.bits256);
     setState(() {
       _output = 'Key generated.';
     });
   }
 
-  void encrypt() async {
+  void _encrypt() async {
     final plainText = textController.text.trim();
 
     var output;
@@ -37,7 +38,7 @@ class _MyAppState extends State<MyApp> {
       output = 'Entry is empty';
     } else {
       var stringToBytes = TypeHelper().stringToBytes(plainText);
-      encryptedPayload = await NativeCrypto().symEncrypt(stringToBytes, aeskey);
+      encrypted = await aes.encrypt(stringToBytes);
       output = 'String successfully encrypted.';
     }
     setState(() {
@@ -45,56 +46,67 @@ class _MyAppState extends State<MyApp> {
     });
   }
 
-  void decrypt() async {
+  void _decrypt() async {
-
     var output;
-    if (encryptedPayload == null || encryptedPayload.isEmpty) {
+    if (encrypted.cipherText == null || encrypted.cipherText.isEmpty) {
       output = 'Encrypt before decrypting!';
     } else {
-      decryptedPayload = await NativeCrypto().symDecrypt(encryptedPayload, aeskey);
+      decryptedPayload = await aes.decrypt(encrypted);
-      output = 'String successfully decrypted:\n\n${TypeHelper().bytesToString(decryptedPayload)}';
+      var bytesToString = TypeHelper().bytesToString(decryptedPayload);
+      output = 'String successfully decrypted:\n\n$bytesToString';
     }
     setState(() {
       _output = output;
     });
   }
 
-  void benchmark(int megabytes) async {
+  Future<String> _benchmark(int megabytes) async {
-
+    String output;
-    var output;
     var bigFile = Uint8List(megabytes * 1000000);
 
     var before = DateTime.now();
-    var encryptedBigFile = await NativeCrypto().symEncrypt(bigFile, aeskey);
+    var encryptedBigFile = await aes.encrypt(bigFile);
     var after = DateTime.now();
 
-    var benchmark = after.millisecondsSinceEpoch - before.millisecondsSinceEpoch;
+    var benchmark =
+        after.millisecondsSinceEpoch - before.millisecondsSinceEpoch;
 
     output = '$megabytes MB\n\nAES Encryption:\n$benchmark ms\n\n';
 
-    var beforeDec = DateTime.now();
+    before = DateTime.now();
-    var decryptedBigFile = await NativeCrypto().symDecrypt(encryptedBigFile, aeskey);
+    await aes.decrypt(encryptedBigFile);
-    var afterDec = DateTime.now();
+    after = DateTime.now();
 
-    print(bigFile.length);
+    benchmark = after.millisecondsSinceEpoch - before.millisecondsSinceEpoch;
-    print(decryptedBigFile.length);
 
-    print(listEquals(bigFile, decryptedBigFile));
+    output += 'AES Decryption:\n$benchmark ms\n\n\n';
 
-    var benchmarkDec = afterDec.millisecondsSinceEpoch - beforeDec.millisecondsSinceEpoch;
+    return output;
-
+  }
-    output += 'AES Decryption:\n$benchmarkDec ms';
 
+  void _testPerf({int megabytes}) async {
+    var output = '';
+    if (megabytes != null) {
+      output = await _benchmark(megabytes);
       setState(() {
       _output = output;
     });
+    } else {
+      setState(() {
+        _bench = 'Open the logcat!';
+      });
+      for (int i=1;i<100;i+=10) {
+        var benchmark = await _benchmark(i);
+        log(benchmark);
+      }
+    }
     
   }
 
   @override
   void initState() {
-    // Generate AES key on init.
+    // Generate AES instance on init.
-    generateKey();
+    _generateKey();
     super.initState();
   }
 
@@ -113,7 +125,8 @@ class _MyAppState extends State<MyApp> {
           centerTitle: true,
           title: const Text('Native Crypto'),
         ),
-        body: Padding(
+        body: SingleChildScrollView(
+          child: Padding(
             padding: const EdgeInsets.fromLTRB(20, 10, 10, 20),
             child: Center(
               child: Column(
@@ -126,17 +139,17 @@ class _MyAppState extends State<MyApp> {
                   ),
                   SizedBox(height: 20),
                   FlatButton(
-                    onPressed: encrypt,
+                      onPressed: _encrypt,
                       color: Colors.blue,
                       child: Text(
                         'Encrypt String',
                         style: TextStyle(color: Colors.white),
                       )),
-                (encryptedPayload != null && encryptedPayload.isNotEmpty)
+                  (encrypted.cipherText != null && encrypted.cipherText.isNotEmpty)
-                ? Text(encryptedPayload.first.toList().toString())
+                      ? Text(encrypted.cipherText.toString())
                       : Container(),
                   FlatButton(
-                    onPressed: decrypt,
+                      onPressed: _decrypt,
                       color: Colors.blue,
                       child: Text(
                         'Decrypt String',
@@ -144,36 +157,75 @@ class _MyAppState extends State<MyApp> {
                       )),
                   SizedBox(height: 20),
                   // Output
-                Text(_output,
+                  Text(
+                    _output,
                     textAlign: TextAlign.center,
-                  style: TextStyle(fontSize: 20, fontWeight: FontWeight.bold),),
+                    style: TextStyle(fontSize: 20, fontWeight: FontWeight.bold),
+                  ),
                   SizedBox(height: 20),
                   FlatButton(
-                    onPressed: () {benchmark(1);},
+                      onPressed: () {
+                        _testPerf(megabytes: 1);
+                      },
                       color: Colors.blue,
                       child: Text(
                         'Benchmark 1 MB',
                         style: TextStyle(color: Colors.white),
                       )),
                   FlatButton(
-                    onPressed: () {benchmark(10);},
+                      onPressed: () {
+                        _testPerf(megabytes: 10);
+                      },
                       color: Colors.blue,
                       child: Text(
                         'Benchmark 10 MB',
                         style: TextStyle(color: Colors.white),
                       )),
                   FlatButton(
-                    onPressed: () {benchmark(50);},
+                      onPressed: () {
+                        _testPerf(megabytes: 50);
+                      },
                       color: Colors.blue,
                       child: Text(
                         'Benchmark 50 MB',
                         style: TextStyle(color: Colors.white),
                       )),
+                  SizedBox(height: 20),
+                  FlatButton(
+                      onPressed: () {
+                        _testPerf();
+                      },
+                      color: Colors.blue,
+                      child: Text(
+                        'Full benchmark',
+                        style: TextStyle(color: Colors.white),
+                      )),
+
+                  (_bench != null && _bench.isNotEmpty)
+                      ? Text(_bench)
+                      : Container(),
                 ],
               ),
             ),
           ),
         ),
+      ),
     );
   }
 }
+
+/// Contains some useful functions.
+class TypeHelper {
+  /// Returns bytes `Uint8List` from a `String`.
+  Uint8List stringToBytes(String source) {
+    var list = source.codeUnits;
+    var bytes = Uint8List.fromList(list);
+    return bytes;
+  }
+
+  /// Returns a `String` from bytes `Uint8List`.
+  String bytesToString(Uint8List bytes) {
+    var string = String.fromCharCodes(bytes);
+    return string;
+  }
+}