AES加密不同结果，在C#和PHP中

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

public class AesEncryption
{
    public static string Encrypt(string plainText, string key, string iv)
    {
        byte[] keyBytes = Encoding.UTF8.GetBytes(key);
        byte[] ivBytes = Encoding.UTF8.GetBytes(iv);

        using (Aes aes = Aes.Create())
        {
            aes.Key = keyBytes;
            aes.IV = ivBytes;

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

            byte[] encryptedBytes = null;

            using (var ms = new System.IO.MemoryStream())
            {
                using (var cs = new CryptoStream(ms, encryptor, CryptoStreamMode.Write))
                {
                    using (var sw = new System.IO.StreamWriter(cs))
                    {
                        sw.Write(plainText);
                    }

                    encryptedBytes = ms.ToArray();
                }
            }

            return Convert.ToBase64String(encryptedBytes);
        }
    }
}

function encrypt($plainText, $key, $iv)
{
    $encryptedBytes = openssl_encrypt($plainText, 'AES-128-CBC', $key, OPENSSL_RAW_DATA, $iv);

    return base64_encode($encryptedBytes);
}