如何解密AES-256-CBC加密字符串

我是C#的新手,我真的需要帮助.我需要在C#中使用AES-256-CBC加密/解密字符串,我发现这是为了加密字符串:

    public static string EncryptString(string message, string KeyString, string IVString)
    {
        byte[] Key = ASCIIEncoding.UTF8.GetBytes(KeyString);
        byte[] IV = ASCIIEncoding.UTF8.GetBytes(IVString);

        string encrypted = null;
        RijndaelManaged rj = new RijndaelManaged();
        rj.Key = Key;
        rj.IV = IV;
        rj.Mode = CipherMode.CBC;

        try
        {
            MemoryStream ms = new MemoryStream();

            using (CryptoStream cs = new CryptoStream(ms, rj.CreateEncryptor(Key, IV), CryptoStreamMode.Write))
            {
                using (StreamWriter sw = new StreamWriter(cs))
                {
                    sw.Write(message);
                    sw.Close();
                }
                cs.Close();
            }
            byte[] encoded = ms.ToArray();
            encrypted = Convert.ToBase64String(encoded);

            ms.Close();
        }
        catch (CryptographicException e)
        {
            Console.WriteLine("A Cryptographic error occurred: {0}", e.Message);
            return null;
        }
        catch (UnauthorizedAccessException e)
        {
            Console.WriteLine("A file error occurred: {0}", e.Message);
            return null;
        }
        catch (Exception e)
        {
            Console.WriteLine("An error occurred: {0}", e.Message);
        }
        finally
        {
            rj.Clear();
        }
        return encrypted;
    }

我试着写一个基于上面代码的解密函数,下面的代码是我做的:

  // Decrypt a byte array into a byte array using a key and an IV 
        private byte[] Decrypt(byte[] cipherData, byte[] Key, byte[] IV)
        {
            byte[] decryptedData;
            //string plaintext = null;
            //MemoryStream ms = new MemoryStream(cipherData);

            RijndaelManaged alg = new RijndaelManaged();
   alg.KeySize = 256;
            alg.BlockSize = 128;
            alg.Key = Key;
            alg.IV = IV;
            alg.Mode = CipherMode.CBC;
            alg.Padding = PaddingMode.Zeros;

            //Array.Copy(Key, 0, IV, 0, IV.Length);

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

            using(MemoryStream ms = new MemoryStream(cipherData))
            {
                using (CryptoStream csDecrypt = new CryptoStream(ms, decryptor, CryptoStreamMode.Read))
                {
                    using (StreamReader sw = new StreamReader(csDecrypt))
                    {
                        sw.ReadToEnd();
                        sw.Close();
                    }

                    csDecrypt.Close();
                    decryptedData = ms.ToArray();
                }
            }

            //byte[] decryptedData = System.Text.Encoding.Unicode.GetBytes(plaintext);
            return decryptedData; 
        }

但这是无稽之谈,它无法解密任何东西.我真的很困惑,需要帮助.感谢您的任何帮助!

P/s:请不要给我其他类似的回答问题,我已经看过了.它们的加密功能与上述加密功能不具有相同的输出,而我需要解密必须由上述功能加密的字符串.我有两个用PHP编写解密函数的朋友和Objective-C,它与上面的加密函数相匹配,让他们再做一次是不好的.