读取字节数组与将字节数组写入文件不一致

所以我的问题很简单。我想加密一些文本并将其像数组的字节一样写入文件，然后我需要读取文件的内容并像parameter一样将数组的字节解密为字符串的另一种方法。方法Encrypt和Decrypt运行良好，我尝试过它，但当我使用FILE中的字节数组时，它引发了异常。

private static byte[] EncryptString(string text,byte[] key,byte[] vektor)
    {
        byte[] array=null;
        // Check arguments.
        if (text == null || text.Length <= 0)
            throw new ArgumentNullException("plainText");
        if (key == null || key.Length <= 0)
            throw new ArgumentNullException("Key");
        if (vektor == null || vektor.Length <= 0)
            throw new ArgumentNullException("Vektor");
        try
        {
            using (DESCryptoServiceProvider provider = new DESCryptoServiceProvider())
            {
                provider.Key = key;
                provider.IV = vektor;
                using (MemoryStream memory = new MemoryStream())
                {
                    using (CryptoStream crypto = new CryptoStream(memory, provider.CreateEncryptor(provider.Key, provider.IV), CryptoStreamMode.Write))
                    {
                        using (StreamWriter writer = new StreamWriter(crypto))
                        {
                            writer.WriteLine(text);
                        }
                    }
                    array = memory.ToArray();
                }
            }
        }
        catch (ArgumentNullException e)
        {
            Console.WriteLine("Error in EncryptString  {0}", e.Message);
        }
        catch (Exception e)
        {
            Console.WriteLine("Error in EncryptString  {0}", e.Message);
        }
        return array;
    }

此方法将字节数组加密为字符串

private static string DecryptByte(byte[] text, byte[] key, byte[] vektor)
    {
        string result = null;
        // Check arguments.
        if (text == null || text.Length <= 0)
            throw new ArgumentNullException("plainText");
        if (key == null || key.Length <= 0)
            throw new ArgumentNullException("Key");
        if (vektor == null || vektor.Length <= 0)
            throw new ArgumentNullException("Key");
        try
        {
            using (DESCryptoServiceProvider provider = new DESCryptoServiceProvider())
            {
                provider.Key=key;
                provider.IV=vektor;
                using (MemoryStream memory = new MemoryStream(text))
                {
                    using (CryptoStream crypto = new CryptoStream(memory, provider.CreateDecryptor(provider.Key, provider.IV), CryptoStreamMode.Read))
                    {
                        using (StreamReader read = new StreamReader(crypto))
                        { 
                            result=read.ReadToEnd();
                        }
                    }
                }
            }
        }
        catch(Exception e)
        {
            Console.WriteLine("Error in DecryptByte:{0}"+e.Message);
        }
        return result;
    }

好吧，我保存加密文本，然后当按下按钮时

private void buttonDecrypt_Click(object sender, RoutedEventArgs e)
    {
        byte[] text=null,helper=null;
        string result = null;
        try
        {
            using (FileStream filestream = File.OpenRead(path))
            {
                helper = new byte[filestream.Length];
                filestream.Read(helper, 0, (int)filestream.Length);
            }
                    using (DESCryptoServiceProvider provider = new DESCryptoServiceProvider())
                    {
                        result = DecryptByte(helper, provider.Key, provider.IV);
                    }
        }
        catch(Exception ex)
        {
            Console.WriteLine("Error v ButtonDecrypt.{0}_____{1}",ex.Message,ex.Data);
        }
    }

所以我的问题是，我从File读取的数据不一样，并且在DecryptByte中抛出了Exception。你能帮我吗？编辑是异常消息为无效数据