从cryptostream读取到流的末尾

Question

我在使用下面的代码时遇到了一些麻烦.我有一个临时位置的文件,需要加密,这个功能加密该数据,然后存储在"pathToSave"位置.

在检查时似乎没有正确处理整个文件 - 我的输出中缺少一些内容,我怀疑它与没有在整个流中运行的while循环有关.

顺便说一句,如果我尝试在while循环后调用CryptStrm.Close(),我会收到一个异常.这意味着如果我尝试解密文件,我会得到一个已经在使用的文件错误!

尝试了所有平常和我在这里看到类似的问题,任何帮助都会很棒.

谢谢

public void EncryptFile(String tempPath, String pathToSave)
    {
        try
        {
            FileStream InputFile = new FileStream(tempPath, FileMode.Open, FileAccess.Read);
            FileStream OutputFile = new FileStream(pathToSave, FileMode.Create, FileAccess.Write);

            RijndaelManaged RijCrypto = new RijndaelManaged();

            //Key
            byte[] Key = new byte[32] { ... };

            //Initialisation Vector
            byte[] IV = new byte[32] { ... };

            RijCrypto.Padding = PaddingMode.None;
            RijCrypto.KeySize = 256;
            RijCrypto.BlockSize = 256;
            RijCrypto.Key = Key;
            RijCrypto.IV = IV;

            ICryptoTransform Encryptor = RijCrypto.CreateEncryptor(Key, IV);

            CryptoStream CryptStrm = new CryptoStream(OutputFile, Encryptor, CryptoStreamMode.Write);

            int data;
            while (-1 != (data = InputFile.ReadByte()))
            {
                CryptStrm.WriteByte((byte)data);
            }
        }
        catch (Exception EncEx)
        {
            throw new Exception("Encoding Error: " + EncEx.Message);
        }
    }

编辑:

我假设我的问题在于加密.我的解密可能是罪魁祸首

        public String DecryptFile(String encryptedFilePath)
    {
        FileStream InputFile = new FileStream(encryptedFilePath, FileMode.Open, FileAccess.Read);

        RijndaelManaged RijCrypto = new RijndaelManaged();

        //Key
        byte[] Key = new byte[32] { ... };

        //Initialisation Vector
        byte[] IV = new byte[32] { ... };

        RijCrypto.Padding = PaddingMode.None;
        RijCrypto.KeySize = 256;
        RijCrypto.BlockSize = 256;
        RijCrypto.Key = Key;
        RijCrypto.IV = IV;

        ICryptoTransform Decryptor = RijCrypto.CreateDecryptor(Key, IV);

        CryptoStream CryptStrm = new CryptoStream(InputFile, Decryptor, CryptoStreamMode.Read);

        String OutputFilePath = Path.GetTempPath() + "myfile.name";
        StreamWriter OutputFile = new StreamWriter(OutputFilePath);

        OutputFile.Write(new StreamReader(CryptStrm).ReadToEnd());

        CryptStrm.Close();
        OutputFile.Close();

        return OutputFilePath;
    }

Answer 1

嗯,这里有几个问题.

1.您将IV的大小设置得太大.如果密钥大小为256,则Rijndael的IV为16字节.如果您尝试使用比该字节更多的字符来设置密钥,则会出现异常.IV大小应设置为块大小/ 8 请参阅MSDN,以便您拥有的IV大小是正确的.

2. 您的填充模式为None.除非您的数据完全是正确的块大小,否则您将遇到问题.您可能想要选择填充模式.
3. 在加密时,通常需要在写入加密流时调用FlushFInalBlock,以确保将所有数据写入流中.

我正在使用内存流发布一些示例代码来显示加密和解密.

var tempData = "This is the text to encrypt. It's not much, but it's all there is.";

using (var rijCrypto = new RijndaelManaged())
{
    byte[] encryptedData;
    rijCrypto.Padding = System.Security.Cryptography.PaddingMode.ISO10126;
    rijCrypto.KeySize = 256;

    using (var input = new MemoryStream(Encoding.Unicode.GetBytes(tempData)))
    using (var output = new MemoryStream())
    {
        var encryptor = rijCrypto.CreateEncryptor();

        using (var cryptStream = new CryptoStream(output, encryptor, CryptoStreamMode.Write))
        {
            var buffer = new byte[1024];
            var read = input.Read(buffer, 0, buffer.Length);
            while (read > 0)
            {
                cryptStream.Write(buffer, 0, read);
                read = input.Read(buffer, 0, buffer.Length);
            }
            cryptStream.FlushFinalBlock();
            encryptedData = output.ToArray();
        }
    }

    using (var input = new MemoryStream(encryptedData))
    using (var output = new MemoryStream())
    {
        var decryptor = rijCrypto.CreateDecryptor();
        using (var cryptStream = new CryptoStream(input, decryptor, CryptoStreamMode.Read))
        {
            var buffer = new byte[1024];
            var read = cryptStream.Read(buffer, 0, buffer.Length);
            while (read > 0)
            {
                 output.Write(buffer, 0, read);
                 read = cryptStream.Read(buffer, 0, buffer.Length);
            }
            cryptStream.Flush();
            var result = Encoding.Unicode.GetString(output.ToArray());
        }
    }
}

Answer 2

读取 CryptoStream 的另一种方法是使用 CopyTo 方法：

...

    using (var output = new MemoryStream())
    {
       cryptStream.CopyTo(output);
       return output.ToArray();
    }

...