GCHQ - The grid decode

// GCHQ.cpp : part 1 - the grid
// (c) 2011 Rich Carless

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


unsigned char code[] = {
    0xeb, 0x04, 0xaf, 0xc2, 0xbf, 0xa3, 0x81, 0xec,   0x00, 0x01, 0x00, 0x00, 0x31, 0xc9, 0x88, 0x0c,
    0x0c, 0xfe, 0xc1, 0x75, 0xf9, 0x31, 0xc0, 0xba,   0xef, 0xbe, 0xad, 0xde, 0x02, 0x04, 0x0c, 0x00,
    0xd0, 0xc1, 0xca, 0x08, 0x8a, 0x1c, 0x0c, 0x8a,   0x3c, 0x04, 0x88, 0x1c, 0x04, 0x88, 0x3c, 0x0c,
    0xfe, 0xc1, 0x75, 0xe8, 0xe9, 0x5c, 0x00, 0x00,   0x00, 0x89, 0xe3, 0x81, 0xc3, 0x04, 0x00, 0x00,
    0x00, 0x5c, 0x58, 0x3d, 0x41, 0x41, 0x41, 0x41,   0x75, 0x43, 0x58, 0x3d, 0x42, 0x42, 0x42, 0x42,
    0x75, 0x3b, 0x5a, 0x89, 0xd1, 0x89, 0xe6, 0x89,   0xdf, 0x29, 0xcf, 0xf3, 0xa4, 0x89, 0xde, 0x89,
    0xd1, 0x89, 0xdf, 0x29, 0xcf, 0x31, 0xc0, 0x31,   0xdb, 0x31, 0xd2, 0xfe, 0xc0, 0x02, 0x1c, 0x06,
    0x8a, 0x14, 0x06, 0x8a, 0x34, 0x1e, 0x88, 0x34,   0x06, 0x88, 0x14, 0x1e, 0x00, 0xf2, 0x30, 0xf6,
    0x8a, 0x1c, 0x16, 0x8a, 0x17, 0x30, 0xda, 0x88,   0x17, 0x47, 0x49, 0x75, 0xde, 0x31, 0xdb, 0x89,
    0xd8, 0xfe, 0xc0, 0xcd, 0x80, 0x90, 0x90, 0xe8,   0x9d, 0xff, 0xff, 0xff, 0x41, 0x41, 0x41, 0x41,
};

unsigned char exe[4096]={0};

// this is base 64 encoded data from png (web site used http://www.rbl.jp/base64.php)
char png_data_base_64[] = {"QkJCQjIAAACR2PFtcCA6q2eaC8SR+8dmD/zNzLQC+td3tFQ4qx8O447TDeuZw5P+0SsbEcYR\n78jKLw=="};

unsigned char png_data_32[] = {
    0x42, 0x42, 0x42, 0x42, 0x32, 0x00, 0x00, 0x00,   0x91, 0xd8, 0xf1, 0x6d, 0x70, 0x20, 0x3a, 0xab,
    0x67, 0x9a, 0x0b, 0xc4, 0x91, 0xfb, 0xc7, 0x66,   0x0f, 0xfc, 0xcd, 0xcc, 0xb4, 0x02, 0xfa, 0xd7,
    0x77, 0xb4, 0x54, 0x38, 0xab, 0x1f, 0x0e, 0xe3,   0x8e, 0xd3, 0x0d, 0xeb, 0x99, 0xc3, 0x93, 0xfe,
    0xd1, 0x2b, 0x1b, 0x11, 0xc6, 0x11, 0xef, 0xc8,   0xca, 0x2f
};

void Decode(const unsigned char *in_buff, unsigned char *out_buff,unsigned char cyper, int len)
{
    for( int i = 0; i < len; ++i )
    {
        out_buff[i] = in_buff[i] ^ cyper;
    }
}

void LongDecode(const unsigned long *in_buff, unsigned long *out_buff,unsigned long cyper, int len)
{
    for( int i = 0; i < len; ++i )
    {
        out_buff[i] = in_buff[i] ^ cyper;
    }
}

void Switch(wchar_t *in_source, wchar_t *out_buff)
{
    ((char*)out_buff)[0] = ((char*)in_source)[1];
    ((char*)out_buff)[1] = ((char*)in_source)[0];
}

int _tmain(int argc, _TCHAR* argv[])
{
    // allows windows to run the code (needed in VS2010+)
    DWORD old = 0;
    BOOL res = VirtualProtect(exe,sizeof(exe),PAGE_EXECUTE_READWRITE,&old);
    // clear some buffer space
    memset(exe,0,4096);
    // code
    memcpy(exe,code,sizeof(code));
    // message to be decoded
    memcpy(exe+sizeof(code),png_data_32,sizeof(png_data_32));
    // run
    ((void(*)(void))&exe)();

    return 0;
}