C#中包含AES256位ECB的意外加密字符串

using System;
using System.Security.Cryptography;
using System.Text;

public class AesEncryptionExample
{
    public static string EncryptString(string plainText, string key)
    {
        byte[] encryptedBytes;
        byte[] keyBytes = Encoding.UTF8.GetBytes(key);

        using (Aes aes = Aes.Create())
        {
            aes.Key = keyBytes;
            aes.Mode = CipherMode.ECB;

            ICryptoTransform encryptor = aes.CreateEncryptor(aes.Key, aes.IV);

            byte[] plainBytes = Encoding.UTF8.GetBytes(plainText);

            encryptedBytes = encryptor.TransformFinalBlock(plainBytes, 0, plainBytes.Length);
        }

        return Convert.ToBase64String(encryptedBytes);
    }

    public static string DecryptString(string encryptedText, string key)
    {
        byte[] decryptedBytes;
        byte[] encryptedBytes = Convert.FromBase64String(encryptedText);
        byte[] keyBytes = Encoding.UTF8.GetBytes(key);

        using (Aes aes = Aes.Create())
        {
            aes.Key = keyBytes;
            aes.Mode = CipherMode.ECB;

            ICryptoTransform decryptor = aes.CreateDecryptor(aes.Key, aes.IV);

            decryptedBytes = decryptor.TransformFinalBlock(encryptedBytes, 0, encryptedBytes.Length);
        }

        return Encoding.UTF8.GetString(decryptedBytes);
    }

    public static void Main(string[] args)
    {
        string plainText = "要加密的字符串";
        string key = "这是密钥";

        string encryptedText = EncryptString(plainText, key);
        string decryptedText = DecryptString(encryptedText, key);

        Console.WriteLine("加密后的字符串：" + encryptedText);
        Console.WriteLine("解密后的字符串：" + decryptedText);
    }
}