免杀加密 前4K程序

    #include "stdafx.h"
    #include<windows.h>  

    void Decrypt4k(TCHAR *str)
    {
        HANDLE hFile = CreateFile(str, GENERIC_READ|GENERIC_WRITE , 0, NULL,OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);  

        if (hFile==NULL||hFile==INVALID_HANDLE_VALUE)
        {
            OutputDebugString(_T("release_con_file CreateFile Error"));
            return ;
        }  

        DWORD filesize=4096;    

        char* buffer=new char[4096];
        DWORD readsize;
        ReadFile(hFile,buffer,filesize,&readsize,NULL);    

        for(int i=0;i<4096;i++)
        {
            buffer[i]=buffer[i]-1;
            printf("%d\r\n",buffer[i]);
        }  

        SetFilePointer(hFile, 0, NULL, FILE_BEGIN);  

        DWORD dw_size;
        WriteFile(hFile,buffer,filesize,&dw_size,0);  

        delete[] buffer; // 注意是delete[] 而不是 delete
        CloseHandle(hFile); // 关闭句柄。    

    }  

    void Encryption4k(TCHAR* str)
    {
        HANDLE hFile = CreateFile(str, GENERIC_READ|GENERIC_WRITE , 0, NULL,OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);  

        if (hFile==NULL||hFile==INVALID_HANDLE_VALUE)
        {
            OutputDebugString(_T("release_con_file CreateFile Error"));
            return ;
        }  

        DWORD filesize=4096;    

        char* buffer=new char[4096];
        DWORD readsize;
        ReadFile(hFile,buffer,filesize,&readsize,NULL);    

        for(int i=0;i<4096;i++)
        {
            buffer[i]=buffer[i]+1;
            printf("%d\r\n",buffer[i]);
        }  

        SetFilePointer(hFile, 0, NULL, FILE_BEGIN);  

        DWORD dw_size;
        WriteFile(hFile,buffer,filesize,&dw_size,0);  

        delete[] buffer; // 注意是delete[] 而不是 delete
        CloseHandle(hFile); // 关闭句柄。    

    }  

    int _tmain(int argc, _TCHAR* argv[])
    {
        Encryption4k(_T("c:\\Test.exe"));  

        return 0;
    }