Flutter加密解密插件cryptology的使用

当然，以下是如何在Flutter应用中使用cryptology插件进行加密和解密的示例代码。cryptology插件提供了对多种加密算法的支持，这里我们以AES加密为例。

首先，你需要在你的pubspec.yaml文件中添加cryptology依赖：

dependencies:
  flutter:
    sdk: flutter
  cryptology: ^x.y.z  # 请替换为最新的版本号

然后运行flutter pub get来安装依赖。

接下来，是一个简单的Flutter应用示例，演示如何使用cryptology进行AES加密和解密：

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

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

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

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

class _MyHomePageState extends State<MyHomePage> {
  final TextEditingController _plainTextController = TextEditingController();
  final TextEditingController _encryptedTextController = TextEditingController();
  final TextEditingController _decryptedTextController = TextEditingController();
  final TextEditingController _keyController = TextEditingController();

  String? _encryptError;
  String? _decryptError;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Flutter Cryptology Demo'),
      ),
      body: Padding(
        padding: const EdgeInsets.all(16.0),
        child: Column(
          children: [
            TextField(
              controller: _keyController,
              decoration: InputDecoration(labelText: 'Encryption Key'),
            ),
            SizedBox(height: 16),
            TextField(
              controller: _plainTextController,
              decoration: InputDecoration(labelText: 'Plain Text'),
              maxLines: 5,
            ),
            SizedBox(height: 16),
            ElevatedButton(
              onPressed: _encrypt,
              child: Text('Encrypt'),
            ),
            SizedBox(height: 16),
            TextField(
              controller: _encryptedTextController,
              decoration: InputDecoration(labelText: 'Encrypted Text'),
              readOnly: true,
              maxLines: 5,
            ),
            SizedBox(height: 16),
            ElevatedButton(
              onPressed: _decrypt,
              child: Text('Decrypt'),
            ),
            SizedBox(height: 16),
            TextField(
              controller: _decryptedTextController,
              decoration: InputDecoration(labelText: 'Decrypted Text'),
              readOnly: true,
              maxLines: 5,
            ),
            SizedBox(height: 16),
            if (_encryptError != null)
              Text(
                'Encrypt Error: $_encryptError',
                style: TextStyle(color: Colors.red),
              ),
            if (_decryptError != null)
              Text(
                'Decrypt Error: $_decryptError',
                style: TextStyle(color: Colors.red),
              ),
          ],
        ),
      ),
    );
  }

  Future<void> _encrypt() async {
    setState(() {
      _encryptedTextController.clear();
      _encryptError = null;
    });

    final String? key = _keyController.text;
    final String? plainText = _plainTextController.text;

    if (key == null || plainText == null) {
      setState(() {
        _encryptError = 'Key and plain text are required.';
      });
      return;
    }

    try {
      final aes = AesCbcWithPkcs7Padding();
      final encrypted = await aes.encrypt(plainText, key: key);
      _encryptedTextController.text = encrypted.base64;
    } catch (e) {
      setState(() {
        _encryptError = e.toString();
      });
    }
  }

  Future<void> _decrypt() async {
    setState(() {
      _decryptedTextController.clear();
      _decryptError = null;
    });

    final String? key = _keyController.text;
    final String? encryptedTextBase64 = _encryptedTextController.text;

    if (key == null || encryptedTextBase64 == null) {
      setState(() {
        _decryptError = 'Key and encrypted text are required.';
      });
      return;
    }

    try {
      final aes = AesCbcWithPkcs7Padding();
      final encrypted = Encrypted.fromBase64(encryptedTextBase64);
      final decrypted = await aes.decrypt(encrypted, key: key);
      _decryptedTextController.text = decrypted;
    } catch (e) {
      setState(() {
        _decryptError = e.toString();
      });
    }
  }
}

解释

1. 依赖添加：在pubspec.yaml文件中添加cryptology依赖。
2. UI布局：使用TextField和ElevatedButton构建了一个简单的UI，允许用户输入密钥、明文、查看加密后的文本以及解密后的文本。
3. 加密函数：_encrypt函数使用AES-CBC-PKCS7填充模式进行加密。用户输入密钥和明文后，点击“Encrypt”按钮，加密后的文本将以Base64格式显示。
4. 解密函数：_decrypt函数使用AES-CBC-PKCS7填充模式进行解密。用户输入密钥和加密后的Base64文本后，点击“Decrypt”按钮，解密后的明文将显示。

注意：AES加密需要一个密钥，密钥的长度和格式取决于具体的算法实现。在实际应用中，密钥管理非常重要，应该妥善保管。

希望这个示例代码对你有所帮助！