1

我在 C# 中有一个加密和解密 .txt 文件的代码。但我需要使用任何扩展名（如 pdf、zip、jpg 等）加密和解密文件。

我搜索蚂蚁试图找到流加密，但我找不到任何..

我正在尝试遵循链接中的代码。我更改了文件路径并放了一些pdf或ppt。它工作正常，但我无法打开解密文件。

  using System;
using System.IO;
using System.Security;
using System.Security.Cryptography;
using System.Runtime.InteropServices;
using System.Text;

namespace CSEncryptDecrypt
{
   class Class1
   {
      //  Call this function to remove the key from memory after use for security
      [System.Runtime.InteropServices.DllImport("KERNEL32.DLL", EntryPoint="RtlZeroMemory")]
      public static extern bool ZeroMemory(IntPtr Destination, int Length);

      // Function to Generate a 64 bits Key.
      static string GenerateKey() 
      {
         // Create an instance of Symetric Algorithm. Key and IV is generated automatically.
         DESCryptoServiceProvider desCrypto =(DESCryptoServiceProvider)DESCryptoServiceProvider.Create();

         // Use the Automatically generated key for Encryption. 
         return ASCIIEncoding.ASCII.GetString(desCrypto.Key);
      }

      static void EncryptFile(string sInputFilename,
         string sOutputFilename, 
         string sKey) 
      {
         FileStream fsInput = new FileStream(sInputFilename, 
            FileMode.Open, 
            FileAccess.Read);

         FileStream fsEncrypted = new FileStream(sOutputFilename, 
            FileMode.Create, 
            FileAccess.Write);
         DESCryptoServiceProvider DES = new DESCryptoServiceProvider();
         DES.Key = ASCIIEncoding.ASCII.GetBytes(sKey);
         DES.IV = ASCIIEncoding.ASCII.GetBytes(sKey);
         ICryptoTransform desencrypt = DES.CreateEncryptor();
         CryptoStream cryptostream = new CryptoStream(fsEncrypted, 
            desencrypt, 
            CryptoStreamMode.Write); 

         byte[] bytearrayinput = new byte[fsInput.Length];
         fsInput.Read(bytearrayinput, 0, bytearrayinput.Length);
         cryptostream.Write(bytearrayinput, 0, bytearrayinput.Length);
         cryptostream.Close();
         fsInput.Close();
         fsEncrypted.Close();
      }

      static void DecryptFile(string sInputFilename, 
         string sOutputFilename,
         string sKey)
      {
         DESCryptoServiceProvider DES = new DESCryptoServiceProvider();
         //A 64 bit key and IV is required for this provider.
         //Set secret key For DES algorithm.
         DES.Key = ASCIIEncoding.ASCII.GetBytes(sKey);
         //Set initialization vector.
         DES.IV = ASCIIEncoding.ASCII.GetBytes(sKey);

         //Create a file stream to read the encrypted file back.
         FileStream fsread = new FileStream(sInputFilename, 
            FileMode.Open, 
            FileAccess.Read);
         //Create a DES decryptor from the DES instance.
         ICryptoTransform desdecrypt = DES.CreateDecryptor();
         //Create crypto stream set to read and do a 
         //DES decryption transform on incoming bytes.
         CryptoStream cryptostreamDecr = new CryptoStream(fsread, 
            desdecrypt,
            CryptoStreamMode.Read);
         //Print the contents of the decrypted file.
         StreamWriter fsDecrypted = new StreamWriter(sOutputFilename);
         fsDecrypted.Write(new StreamReader(cryptostreamDecr).ReadToEnd());
         fsDecrypted.Flush();
         fsDecrypted.Close();
      } 

      static void Main()
      {
         // Must be 64 bits, 8 bytes.
         // Distribute this key to the user who will decrypt this file.
         string sSecretKey;

         // Get the Key for the file to Encrypt.
         sSecretKey = GenerateKey();

         // For additional security Pin the key.
         GCHandle gch = GCHandle.Alloc( sSecretKey,GCHandleType.Pinned );

         // Encrypt the file.        
         EncryptFile(@"C:\MyData.txt", 
            @"C:\Encrypted.txt", 
            sSecretKey);

         // Decrypt the file.
         DecryptFile(@"C:\Encrypted.txt", 
            @"C:\Decrypted.txt", 
            sSecretKey);

         // Remove the Key from memory. 
         ZeroMemory(gch.AddrOfPinnedObject(), sSecretKey.Length * 2);
         gch.Free();
      }
   }
}
4

2 回答 2

0

感谢您的回复。我找到了原因。我应该在decryptFile函数中使用filestream而不是streamwriter

于 2012-12-10T18:45:12.477 回答
-1

按照我用来安全地序列化对象的例程。也许它可以帮助您了解流加密的工作原理：

public bool Save(string filename, object toSerialize)
    {

        byte[] SALT = new byte[]
        {0x26, 0xdc, 0xff, 0x00, 0xad, 0xed, 0x7a, 0xee, 0xc5, 0xfe, 0x07, 0xaf, 0x4d, 0x08, 0x22, 0x3c};

        string EncryptionKey = "MYPASSWORD";

        //basic serialization
        IFormatter form = new BinaryFormatter();
        var stream = new MemoryStream();
        form.Serialize(stream, toSerialize);

        //cryptography preparation
        var alg = new RijndaelManaged();
        var pdb = new Rfc2898DeriveBytes(EncryptionKey, SALT);
        alg.Key = pdb.GetBytes(32);
        alg.IV = pdb.GetBytes(16);

        stream.Position = 0;
        //cryptorgraphy serialization
        var encStream = new MemoryStream();
        var cryptoStream = new CryptoStream(encStream, alg.CreateEncryptor(), CryptoStreamMode.Write);
        cryptoStream.Write(stream.ToArray(), 0, (int)stream.Length);
        cryptoStream.FlushFinalBlock();

        var outputFileStream = new FileStream(fileName, FileMode.Create);
        outputFileStream.Write(encStream.ToArray(), 0, (int)encStream.Length);
        outputFileStream.Close();


        return true;
    }

我还可以为您提供反序列化加密流的来源。

于 2012-12-09T18:11:10.233 回答