如何在flutter sharedprefrence中存储加密类型

import 'package:flutter/material.dart';
import 'package:shared_preferences/shared_preferences.dart';
import 'package:crypto/crypto.dart';
import 'dart:convert';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Shared Preferences',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  final String key = 'encrypted_data';

  Future<void> saveEncryptedData(String data) async {
    SharedPreferences prefs = await SharedPreferences.getInstance();
    String encryptedData = encryptData(data); // 使用加密函数对数据进行加密
    await prefs.setString(key, encryptedData);
  }

  String encryptData(String data) {
    // 在这里编写你的加密算法
    // 例如使用AES加密算法
    // ...
    return encryptedData;
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Flutter Shared Preferences'),
      ),
      body: Center(
        child: RaisedButton(
          child: Text('Save Encrypted Data'),
          onPressed: () {
            saveEncryptedData('Hello World');
          },
        ),
      ),
    );
  }
}