You can read about the setcookie() function here:
http://php.net/manual/en/function.setcookie.php
bool setcookie ( string $name [, string $value = "" [, int $expire = 0 [, string $path = "" [, string $domain = "" [, bool $secure = false [, bool $httponly = false ]]]]]] )
It looks like if you wanted to set the secure and httponly flags it would be:
setcookie("AutoLoginUN", "".((isset($_POST["Log_In_group_Email"]))?$_POST["Log_In_group_Email"]:"") ."", time()+(60*60*24*30), "/", "",true ,true);