如何在flutter的其他设备上对一个字符串进行加密和解密？

import 'package:crypto/crypto.dart';
import 'dart:convert';

String encryptString(String input, String key) {
  var bytes = utf8.encode(key);
  var digest = sha256.convert(bytes);

  final keyBytes = digest.bytes;
  final iv = IV.fromLength(16); // 初始化向量，长度根据加密算法而定

  final encrypter = Encrypter(AES(Key(keyBytes)), iv: iv);
  final encrypted = encrypter.encrypt(input);

  return encrypted.base64;
}

String decryptString(String input, String key) {
  var bytes = utf8.encode(key);
  var digest = sha256.convert(bytes);

  final keyBytes = digest.bytes;
  final iv = IV.fromLength(16); // 初始化向量，长度根据加密算法而定

  final encrypter = Encrypter(AES(Key(keyBytes)), iv: iv);
  final decrypted = encrypter.decrypt64(input);

  return decrypted;
}