What library should be used to identify guests on the site?

Question

User identification

Hello.
There is a task to identify guests on the site and block access to some of them when certain limits are exceeded.
By guests, I mean users who do not enter any identifying information about themselves.
I understand that there is no way to stop bots or hackers at the client level, but I would like to be able to unambiguously block users who do not have serious technical skills.
A couple of years ago I read an article on Habré about a library that can remember and identify the client even when changing the browser. The library left its labels in all available places (cookie, web-storage, flash player cache and other possible places). Unfortunately, I could not find this library now. But I will be very grateful if you remind me what it is called or tell me another case of combating abuse by guests.

Answer 1

https://habr.com/company/oleg-bunin/blog/321294/
https://whoer.net/blog/article/everycookie-neubiva...