Flutter加密解密插件rust_crypto的使用

在Flutter中使用Rust进行加密解密操作可以通过flutter_rust_bridge插件来实现。flutter_rust_bridge允许你在Flutter中调用Rust代码，从而利用Rust的强大性能和安全特性。下面是一个简单的示例，展示如何在Flutter中使用Rust进行加密和解密操作。

1. 创建Flutter项目

首先，创建一个新的Flutter项目：

flutter create flutter_rust_crypto_example
cd flutter_rust_crypto_example

2. 添加flutter_rust_bridge依赖

在pubspec.yaml中添加flutter_rust_bridge依赖：

dependencies:
  flutter:
    sdk: flutter
  flutter_rust_bridge: ^1.0.0

然后运行flutter pub get来获取依赖。

3. 创建Rust项目

在Flutter项目的根目录下创建一个Rust项目：

cargo new --lib native

编辑native/Cargo.toml文件，添加flutter_rust_bridge和rust-crypto依赖：

[package]
name = "native"
version = "0.1.0"
edition = "2018"

[lib]
crate-type = ["cdylib"]

[dependencies]
flutter_rust_bridge = "1.0.0"
rust-crypto = "0.2.36"

4. 编写Rust代码

在native/src/lib.rs中编写加密解密的Rust代码：

use flutter_rust_bridge::frb;
use crypto::symmetriccipher::BlockEncryptor;
use crypto::aes::cbc_encryptor;
use crypto::buffer::{RefReadBuffer, RefWriteBuffer, BufferResult};
use crypto::blockmodes::PkcsPadding;
use crypto::symmetriccipher::BlockDecryptor;
use crypto::aes::cbc_decryptor;

#[frb]
pub fn encrypt(data: Vec<u8>, key: Vec<u8>, iv: Vec<u8>) -> Vec<u8> {
    let mut encryptor = cbc_encryptor(
        crypto::aes::KeySize::KeySize256,
        &key,
        &iv,
        PkcsPadding,
    );

    let mut result = Vec::new();
    let mut read_buffer = RefReadBuffer::new(&data);
    let mut buffer = [0; 4096];
    let mut write_buffer = RefWriteBuffer::new(&mut buffer);

    loop {
        let result_code = encryptor.encrypt(&mut read_buffer, &mut write_buffer, true);
        result.extend(write_buffer.take_read_buffer().take_remaining().iter().cloned());

        match result_code {
            BufferResult::BufferUnderflow => break,
            BufferResult::BufferOverflow => {}
        }
    }

    result
}

#[frb]
pub fn decrypt(data: Vec<u8>, key: Vec<u8>, iv: Vec<u8>) -> Vec<u8> {
    let mut decryptor = cbc_decryptor(
        crypto::aes::KeySize::KeySize256,
        &key,
        &iv,
        PkcsPadding,
    );

    let mut result = Vec::new();
    let mut read_buffer = RefReadBuffer::new(&data);
    let mut buffer = [0; 4096];
    let mut write_buffer = RefWriteBuffer::new(&mut buffer);

    loop {
        let result_code = decryptor.decrypt(&mut read_buffer, &mut write_buffer, true);
        result.extend(write_buffer.take_read_buffer().take_remaining().iter().cloned());

        match result_code {
            BufferResult::BufferUnderflow => break,
            BufferResult::BufferOverflow => {}
        }
    }

    result
}

5. 生成Flutter-Rust桥接代码

在Flutter项目中运行以下命令来生成桥接代码：

flutter_rust_bridge_codegen --rust-input native/src/lib.rs --dart-output lib/bridge_generated.dart --llvm-path /path/to/llvm

确保你已经安装了flutter_rust_bridge_codegen，并且指定了正确的LLVM路径。

6. 在Flutter中调用Rust函数

在lib/main.dart中调用Rust的加密解密函数：

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

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(title: Text('Flutter Rust Crypto Example')),
        body: Center(
          child: FutureBuilder(
            future: _performCrypto(),
            builder: (context, snapshot) {
              if (snapshot.connectionState == ConnectionState.waiting) {
                return CircularProgressIndicator();
              } else if (snapshot.hasError) {
                return Text('Error: ${snapshot.error}');
              } else {
                return Text('Result: ${snapshot.data}');
              }
            },
          ),
        ),
      ),
    );
  }

  Future<String> _performCrypto() async {
    final api = NativeImpl();

    final key = List<int>.generate(32, (i) => i);
    final iv = List<int>.generate(16, (i) => i);
    final data = [1, 2, 3, 4, 5];

    final encrypted = await api.encrypt(data, key, iv);
    final decrypted = await api.decrypt(encrypted, key, iv);

    return 'Encrypted: $encrypted\nDecrypted: $decrypted';
  }
}

7. 运行项目

确保你已经配置好了Rust的编译环境，然后运行Flutter项目：

flutter run