从加密流读取到流的末尾

本文关键字：加密 密流 读取 | 更新日期: 2023-09-27 18:28:07

我在下面的代码中遇到了一些问题。我在一个需要加密的临时位置有一个文件，该函数对数据进行加密，然后将其存储在"pathToSave"位置。

检查时似乎没有正确处理整个文件——我的输出中缺少一些位，我怀疑这与while循环没有贯穿整个流有关。

顺便说一句，如果我在while循环之后尝试调用CryptStrm.Close（），我会收到一个异常。这意味着，如果我试图解密文件，我会得到一个已经在使用的文件错误！

尝试了所有的常规，我在这里查看了类似的问题，任何帮助都将是伟大的。

感谢

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：

我已经假设我的问题是加密。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;
    }

从加密流读取到流的末尾

好吧，这里有几个地方出了问题。

1.您的IV设置太大。如果密钥大小为256，则Rijndael的IV为16字节。如果您尝试设置的密钥的字节数超过此值，则会出现异常IV大小应该设置为块大小/8请参阅MSDN，这样您的IV大小是正确的。

  1. 您的填充模式为"无"。除非您的数据块大小完全正确，否则您将遇到问题。您可能想要选择填充模式
  2. 加密时，通常需要在写入加密流时调用FlushFInalBlock，以确保所有数据都写入流中

我发布了一些使用内存流的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());
        }
    }
}

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();
    }
...

必须首先指定KeySize。这看起来像一个错误，例如，这适用于

            using (var aes = new AesManaged())
            {
                aes.KeySize = 256;
                aes.Mode = CipherMode.CBC;
                aes.IV = iv;
                aes.Key = passwordHash;
                aes.Padding = PaddingMode.PKCS7;

但这不是

            using (var aes = new AesManaged())
            {
                aes.Mode = CipherMode.CBC;
                aes.IV = iv;
                aes.Key = passwordHash;
                aes.Padding = PaddingMode.PKCS7;
                aes.KeySize = 256;
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