C++实现简单异或加密算法

#pragma once
#include <iostream>

class NXCORE_API XorCrypt
{
public:
static std::string Xor(__in const std::string& input,
__in const std::string& key);
static bool Encrypt(__in const std::string& input,
__in const std::string& output, __in const std::string& key);
static bool Decrypt(__in const std::string& input,
__out std::string& output, __in const std::string& key);
static bool EncryptFile(__in const std::string& input,
__in const std::string& output, __in const std::string& key);
static bool DecryptFile(__in const std::string& input,
__in const std::string& output, __in const std::string& key);
};

#include "stdafx.h"
#include "XorCrypt.h"

std::string XorCrypt::Xor(__in const std::string& input,
__in const std::string& key)
{
std::string output;
output.resize(input.size(), '\0');
for (unsigned int i = 0, j = 0; i < input.size(); i++)
output[i] = input[i] ^ key[j == key.size() ? 0 : j++];

return output;
}

bool XorCrypt::Encrypt(__in const std::string& input,
__in const std::string& output, __in const std::string& key)
{
std::string encrypt = Xor(input, key);
HANDLE hFile = ::CreateFileA(output.c_str(), GENERIC_READ | GENERIC_WRITE,
0, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
if (hFile == INVALID_HANDLE_VALUE)
return false;
unsigned long written = 0;
::WriteFile(hFile, encrypt.c_str(), encrypt.size(), &written, NULL);
::FlushFileBuffers(hFile);
::CloseHandle(hFile);
return true;
}

bool XorCrypt::Decrypt(__in const std::string& input,
__out std::string& output, __in const std::string& key)
{

HANDLE hFile = ::CreateFileA(input.c_str(), GENERIC_READ,
0, NULL, OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
if (hFile == INVALID_HANDLE_VALUE)
return false;
unsigned long fileSize = ::GetFileSize(hFile, NULL);
char* buff = new char[fileSize + 1];
memset(buff, 0, fileSize + 1);
unsigned long readSize = 0;
::ReadFile(hFile, buff, fileSize, &readSize, NULL);

output.resize(fileSize);
memcpy(const_cast<char*>(output.c_str()), buff, fileSize);

output = Xor(output, key);
::CloseHandle(hFile);
delete buff;
return true;
}

bool XorCrypt::EncryptFile(__in const std::string& input,
__in const std::string& output, __in const std::string& key)
{
HANDLE hFile = ::CreateFileA(input.c_str(), GENERIC_READ,
0, NULL, OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
if (hFile == INVALID_HANDLE_VALUE)
return false;
unsigned long fileSize = ::GetFileSize(hFile, NULL);
char* buff = new char[fileSize + 1];
memset(buff, 0, fileSize + 1);
unsigned long readSize = 0;
::ReadFile(hFile, buff, fileSize, &readSize, NULL);
::CloseHandle(hFile);
std::string data;
data.resize(fileSize);
memcpy(const_cast<char*>(data.c_str()), buff, fileSize);
delete buff;
return Encrypt(data, output, key);
}

bool XorCrypt::DecryptFile(__in const std::string& input,
__in const std::string& output, __in const std::string& key)
{
std::string data;
if (!Decrypt(input, data, key))
return false;
HANDLE hFile = ::CreateFileA(output.c_str(), GENERIC_READ | GENERIC_WRITE,
0, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
if (hFile == INVALID_HANDLE_VALUE)
return false;
unsigned long written = 0;
::WriteFile(hFile, data.c_str(), data.size(), &written, NULL);
::FlushFileBuffers(hFile);
::CloseHandle(hFile);
return true;
}