Cache the page with output class

Hi,
I want to cache output for each user IP, not URI
Example the $this->output->cache(10); cache the page for domain.com/search
But I want to cache with the user's IP
Actually, I try to cache pages for each user not only for the domain
I changed URI code to IP in Output.php (md5($_SERVER['REMOTE_ADD']))
Is that the right way to cache a page for each user?