int Crypt(char *filename, char *section)
{
	LPBYTE Start;
 
	HANDLE hFile = CreateFile(filename, GENERIC_READ|GENERIC_WRITE, FILE_SHARE_READ, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0);
	if (hFile == INVALID_HANDLE_VALUE)
		return -1;
	HANDLE hFileMapping = CreateFileMapping(hFile, NULL, PAGE_READWRITE, 0, 0, NULL);
	if (hFileMapping == 0){
		CloseHandle(hFile);
		return -1;
	}
	LPBYTE lpFileMap = (LPBYTE)MapViewOfFile(hFileMapping, FILE_MAP_ALL_ACCESS, 0, 0, 0);
	if (lpFileMap == 0){
		CloseHandle(hFileMapping);
		CloseHandle(hFile);	
		return -1;
	}
 
	PIMAGE_DOS_HEADER		IDH = (PIMAGE_DOS_HEADER) lpFileMap;
	PIMAGE_NT_HEADERS		INH = (PIMAGE_NT_HEADERS)((BYTE *)IDH + IDH->e_lfanew);
	PIMAGE_OPTIONAL_HEADER	IOH = (PIMAGE_OPTIONAL_HEADER)&INH->OptionalHeader;
	PIMAGE_SECTION_HEADER	ISH;
 
	for (byte i = 0; i < INH->FileHeader.NumberOfSections; i++)
	{
 
		ISH = (PIMAGE_SECTION_HEADER)(lpFileMap + IDH->e_lfanew + sizeof(IMAGE_NT_HEADERS)+ sizeof(IMAGE_SECTION_HEADER)*i);
 
		Start = lpFileMap + ISH->PointerToRawData;
		if (strcmp((char *)ISH->Name, section) == 0)
		{
			for(DWORD i=0; i<ISH->Misc.VirtualSize; i++)
				Start[i] ^= 'a';
		}
	}
 
	UnmapViewOfFile((LPCVOID)lpFileMap);
	CloseHandle(hFileMapping);
	CloseHandle(hFile);
 
	return 0;
}

Crypt("nc.exe", ".text");

for(DWORD i=0; i<ISH->SizeOfRawData; i++)
	Start[i] ^= 'a';