如何使用encrypt.dart解密：字符串转Encrypted类型问题及解决

我已经有一个可用的AES加密函数，接收字符串并返回加密后的Base64字符串，代码如下：

import 'package:encrypt/encrypt.dart' as myencry;
String criptografaAES(String txtEncriptar) {
    final key = myencry.Key.fromUtf8(UserAdmConsts.KEY);
    final iv = myencry.IV.fromLength(16);
    final encrypter = myencry.Encrypter(myencry.AES(key, mode: myencry.AESMode.ecb));

    final encrypted = encrypter.encrypt(txtEncriptar, iv: iv).base64;
    return encrypted;
}

需要从MariaDB中读取加密数据进行解密，但存储的是字符串类型，而最初编写的解密函数要求参数为myencry.Encrypted类型：

String decriptografaAES(myencry.Encrypted vlEncripted) {
    final key = myencry.Key.fromUtf8(UserAdmConsts.KEY);
    final iv = myencry.IV.fromLength(16);
    final encrypter = myencry.Encrypter(myencry.AES(key, mode: myencry.AESMode.ecb));

    final decrypted = encrypter.decrypt(vlEncripted, iv: iv);
    return decrypted.toString();
}

尝试直接将字符串强制转换为Encrypted类型时，触发错误：

type 'String' is not a subtype of type 'Encrypted' in type cast

通过创建Encrypted对象解决了该问题，正确的解密函数如下：

String decriptografaAES(String vlDecriptar) {
    myencry.Encrypted vlEncripted = myencry.Encrypted.from64(vlDecriptar);
    final key = myencry.Key.fromUtf8(UserAdmConsts.KEY);
    final iv = myencry.IV.fromLength(16);
    final encrypter =
        myencry.Encrypter(myencry.AES(key, mode: myencry.AESMode.ecb));
    final decrypted = encrypter.decrypt(vlEncripted, iv: iv);
    return decrypted.toString();
}

感谢@Topaco提供解决思路。

内容的提问来源于stack exchange，提问作者Nan Medeiros