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I'm making a logging system that does not allow access from different computers to a user. You can only do this from the computer assigned to you.

What data can I save from the client and then compare and verify that the PC from which you access it matches the one registered in the system?

Considering that I can not use the IP address, I can access it with a router from different computers.

The language I use is PHP.

I just want to know what information can be stored on the visitor's computer to make the comparison later. Many Thanks.