Flutter 数据加密插件 RNCryptor 的使用

RNCryptor 是一个与 Rob Napier 的 RNCryptor 兼容的高级 AES 加密/解密库，适用于 iOS。该实现基于 JSCryptor，并在底层使用了 pointycastle。

使用方法

1. 导入包

首先在 Dart 代码中导入 RNCryptor 包：

import 'package:rncryptor/rncryptor.dart';

2. 使用密码进行加密和解密

你可以使用 encrypt 方法通过指定的密码来加密文本：

var encrypted = RNCryptor.encrypt('my password', 'some plain text');

同样，使用 decrypt 方法可以解密加密后的文本：

var decrypted = RNCryptor.decrypt('my password', 'an encrypted message');

3. 使用密钥进行加密和解密

由于将密码转换为密钥的过程是故意设计得较慢的，如果你的应用程序需要频繁地加密/解密大量短消息，使用密钥会更高效。

你可以使用 generateKey 方法生成一个新的密钥：

var salt = RNCryptor.generateSalt();
var encryptKey = RNCryptor.generateKey('my password', salt);

然后使用 encryptWithKey 方法加密消息：

var hmacKey = RNCryptor.generateKey('my password', RNCryptor.generateSalt());
var encrypted = RNCryptor.encryptWithKey(encryptKey, hmacKey, 'some plain text');

使用 decryptWithKey 方法解密消息：

var decrypted = RNCryptor.decryptWithKey(encryptKey, hmacKey, 'an encrypted message', checkHmac: false);

示例 Demo

以下是一个完整的 Flutter 示例应用，展示了如何使用 RNCryptor 进行加密和解密操作。

import 'package:flutter/material.dart';
import 'package:rncryptor/rncryptor.dart';

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

class MyApp extends StatelessWidget {
  [@override](/user/override)
  Widget build(BuildContext context) {
    return MaterialApp(
        title: 'RNCryptor Demo',
        theme: ThemeData(
          primarySwatch: Colors.blue,
        ),
        home: HomePage());
  }
}

class HomePage extends StatelessWidget {
  final TextEditingController controller = TextEditingController();
  final encryptionKey =
      RNCryptor.generateKey('some_strong_password', RNCryptor.generateSalt());
  final hmacKey =
      RNCryptor.generateKey('some_strong_password', RNCryptor.generateSalt());

  void onEncrypt(BuildContext context) {
    var password = 'some_strong_password';
    var encrypted = RNCryptor.encrypt(password, controller.text);
    var decrypted = RNCryptor.decrypt(password, encrypted);
    showDialog(
        context: context,
        builder: (BuildContext context) {
          return AlertDialog(
              title: Text("Encrypted text"),
              content: Column(children: [
                Text(encrypted),
                SizedBox(height: 12),
                Text('Decrypted: $decrypted')
              ]),
              actions: [
                TextButton(
                    child: Text('Ok'),
                    onPressed: () {
                      Navigator.of(context).pop();
                    })
              ]);
        });
  }

  void onEncrypt2(BuildContext context) {
    var encrypted =
        RNCryptor.encryptWithKey(encryptionKey, hmacKey, controller.text);
    var decrypted = RNCryptor.decryptWithKey(encryptionKey, hmacKey, encrypted,
        checkHmac: false);
    showDialog(
        context: context,
        builder: (BuildContext context) {
          return AlertDialog(
              title: Text("Encrypted text"),
              content: Column(children: [
                Text(encrypted),
                SizedBox(height: 12),
                Text('Decrypted: $decrypted')
              ]),
              actions: [
                TextButton(
                    child: Text('Ok'),
                    onPressed: () {
                      Navigator.of(context).pop();
                    })
              ]);
        });
  }

  [@override](/user/override)
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(title: Text('RNCryptor Demo')),
        body: SafeArea(
            child: Padding(
                padding: EdgeInsets.fromLTRB(20, 20, 20, 20),
                child: Column(children: [
                  TextField(
                      controller: controller,
                      decoration: InputDecoration(hintText: 'Text to encrypt')),
                  SizedBox(height: 12),
                  ElevatedButton(
                      onPressed: () => onEncrypt(context),
                      child: Text('Encrypt with password')),
                  SizedBox(height: 12),
                  ElevatedButton(
                      onPressed: () => onEncrypt2(context),
                      child: Text('Encrypt with key')),
                ]))));
  }
}