std::stringstream bestring;
__int64 steamID = 76561197996545192;
__int8 i = 0, parts[8] = { 0 };
do parts[i++] = steamID & 0xFF;
while (steamID >>= 8);

bestring << "BE";
for (int i = 0; i < sizeof(parts); i++) {
	bestring << char(parts[i]);
}

// I used this md5 library http://www.zedwood.com/article/cpp-md5-function
std::cout << md5(bestring.str()) << std::endl;