如何加速这种加密方法C#Filestream

Question

我有加密方法,运行缓慢.加密数百MB的数据大约需要20分钟.我不确定我是否采取了正确的方法.任何帮助,想法,建议将不胜感激.

    private void AES_Encrypt(string inputFile, string outputFile, byte[] passwordBytes, byte[] saltBytes)
    { 
        FileStream fsCrypt = new FileStream(outputFile, FileMode.Create);

        RijndaelManaged AES = new RijndaelManaged();

        AES.KeySize = 256;
        AES.BlockSize = 128;


        var key = new Rfc2898DeriveBytes(passwordBytes, saltBytes, 1000);
        AES.Key = key.GetBytes(AES.KeySize / 8);
        AES.IV = key.GetBytes(AES.BlockSize / 8);
        AES.Padding = PaddingMode.Zeros;

        AES.Mode = CipherMode.CBC;

        CryptoStream cs = new CryptoStream(fsCrypt,
             AES.CreateEncryptor(),
            CryptoStreamMode.Write);

        FileStream fsIn = new FileStream(inputFile, FileMode.Open);

        int data;
        while ((data = fsIn.ReadByte()) != -1)
            cs.WriteByte((byte)data);

        fsCrypt.Flush();
        cs.Flush();
        fsIn.Flush();

        fsIn.Close();
        cs.Close();
        fsCrypt.Close();
}

谢谢你的帮助!

Answer 1

虽然加密速度很慢,但我不希望这是问题.我怀疑这是逐字节的IO导致不必要的开销.解决问题的最简单方法是通过明智的调用Stream.CopyTo- 当你处于它时,你应该使用using语句来适当地清理:

private void AesEncrypt(string inputFile, string outputFile, byte[] passwordBytes, byte[] saltBytes)
{ 
    var key = new Rfc2898DeriveBytes(passwordBytes, saltBytes, 1000);
    RijndaelManaged aes = new RijndaelManaged
    {
        KeySize = 256,
        BlockSize = 128,
        Key = key.GetBytes(AES.KeySize / 8),
        IV = key.GetBytes(AES.BlockSize / 8),
        Padding = PaddingMode.Zeros,
        Mode = CipherMode.CBC
    };

    using (var output = File.Create(outputFile))
    {
        using (var crypto = new CryptoStream(output, aes.CreateEncryptor(), CryptoStreamMode.Write))
        {
            using (var input = File.OpenRead(inputFile))
            {
                input.CopyTo(crypto);
            }
        }
    }
}

如其他答案所述,这不是产生IV的好方法.一般来说,我更愿意使用Rijndael.Create()而不是指定RijndaelManaged- 而且你可能也想要使用一个using语句.

Answer 2

您正在一次读取一个字节.这会产生很多开销.

要加快处理速度,请立即开始使用更多字节或调用内部复制功能:

fsIn.CopyTo(cs);

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