在C＃中使用RC4加密算法加密文件 [英] Encrypting files using RC4 encryption algorithm in C#

问题描述

我的问题是，如何使用RC4加密算法在C＃中加密和解密文件？

这不是这些问题的重复：

• 什么是NullReferenceException，如何解决？




• RC4算法：无法加密/解密客户端使用Javascript和服务器c＃




• C＃中的RC4 128位加密

一瞥，这个问题将会像这个问题的一个副本，但是，它大约7个月大，而且还没有直接解决问题的工作代码的答案。

然而，我提到了以下链接，但是他们都没有回答完全问题，实际上完全没有问题。

• http://www.codeproject.com/Articles/5719/Simple-encrypting-and-decrypting-data-in -C




• http://www.codeproject.com/Articles/5068/RC-Encryption-Algorithm-C-Version

我知道Visual Studio 2013中内置的System.Security.Cryptography库支持RC2，但现在我要关注的是RC4，作为一项研究。我知道这是弱的是的，但我仍在使用它。没有重要的数据将要使用此加密。

最好使用代码示例，它接受一个流作为输入。我引起了很大的混乱，因为我没有正确地描述我的疑虑。我选择了一个流输入，由于担心任何其他输入可能会导致处理大文件的速度降低。

规格：.NET Framework 4.5 ，C＃，WinForms。

解决方案

免责声明： / em>不能正确实现和/或安全。

以下是使用 BouncyCastle 的RC4Engine：

  //加密/解密键作为字节数组
 var key = Encoding.UTF8.GetBytes（secretpassword）; 
 var cipher = new RC4Engine（）; 
 var keyParam = new KeyParameter（key）; 
 
 //用于解密文件只需将第一个参数转换为false 
 cipher.Init（true，keyParam）; 
 
使用（var inputFile = new FileStream（@C：\path\to\your\input.file，FileMode.Open，FileAccess.Read））
使用（var outputFile = new FileStream（@C：\path\to\your\output.file，FileMode.OpenOrCreate，FileAccess.Write））
 {
 //处理文件4KB一次。 
 byte [] buffer = new byte [1024 * 4]; 
 long totalBytesRead = 0; 
 long totalBytesToRead = inputFile.Length; 
 while（totalBytesToRead> 0）
 {
 //确保您的方法被标记为async 
 int read = await inputFile.ReadAsync（buffer，0，buffer.Length ）; 
 
 //如果我们没有读任何东西（EOF），则断开循环
 if（read == 0）
 {
 break; 
} 
 
 totalBytesRead + = read; 
 totalBytesToRead  -  = read; 
 
 byte [] outBuffer = new byte [1024 * 4]; 
 cipher.ProcessBytes（buffer，0，read，outBuffer，0）; 
 await outputFile.WriteAsync（outBuffer，0，read）; 
} 
} 
  

生成的文件使用本网站，似乎按预期工作。

My question is, how do I encrypt and decrypt a file in C# using the RC4 encryption algorithm?

This is not a duplicate of these questions:

• What is a NullReferenceException, and how do I fix it?

• RC4 Algorithm: Unable to Encrypt / Decrypt data where client uses Javascript and Server c#

• RC4 128 bit encryption in C#

I do however acknowledge that at first glance, this question will appear like a duplicate of this question, however, it is around 7 months old, and still has no answer with working code that solves the question directly.

I have however referred to the below links, but none of them answers the question fully, or in fact, at all.

• http://www.codeproject.com/Articles/5719/Simple-encrypting-and-decrypting-data-in-C

• http://www.codeproject.com/Articles/5068/RC-Encryption-Algorithm-C-Version

I do know that the built-in System.Security.Cryptography library in Visual Studio 2013 supports RC2, but what I want to focus on right now is RC4, as part of a research. I know it is weak yes, but I'm still using it. No important data is going to be using this encryption.

Preferably with a code example, that accepts a stream as an input. I have caused great confusion, as I did not describe my concerns properly. I am opting for a stream input, due to the concern that any kind of other input may cause a decrease in the speed of processing large files.

Specifications: NET Framework 4.5, C#, WinForms.

解决方案

Disclaimer: While this code works, it might not be correctly implemented and/or secure.

Here's an example of file encryption/decryption using the BouncyCastle's RC4Engine:

// You encryption/decryption key as a bytes array
var key = Encoding.UTF8.GetBytes("secretpassword");
var cipher = new RC4Engine();
var keyParam = new KeyParameter(key);

// for decrypting the file just switch the first param here to false
cipher.Init(true, keyParam);

using (var inputFile = new FileStream(@"C:\path\to\your\input.file", FileMode.Open, FileAccess.Read))
using (var outputFile = new FileStream(@"C:\path\to\your\output.file", FileMode.OpenOrCreate, FileAccess.Write))
{
    // processing the file 4KB at a time.
    byte[] buffer = new byte[1024 * 4];
    long totalBytesRead = 0;
    long totalBytesToRead = inputFile.Length;
    while (totalBytesToRead > 0)
    {
        // make sure that your method is marked as async
        int read = await inputFile.ReadAsync(buffer, 0, buffer.Length);

        // break the loop if we didn't read anything (EOF)
        if (read == 0)
        {
            break;
        }

        totalBytesRead += read;
        totalBytesToRead -= read;

        byte[] outBuffer = new byte[1024 * 4];
        cipher.ProcessBytes(buffer, 0, read, outBuffer,0);
        await outputFile.WriteAsync(outBuffer,0,read);
    }
}

The resulting file was tested using this website and it appears to be working as expected.

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