Background (not necessary to read; just what makes me ask):
Say someone's computer has either been hacked, or is running software run by $LARGE_EVIL_CORPORATION, and the hacker/$L wants to collect as much information as possible about the person whose hardware they've owned.
Now assume the hacker/$L also has software running on another of the person's machines. On one machine, the user does personal things (e.g. finances), and on the other machine they don't (i.e. they try to remain relatively anonymous).
But, since they're the same person, they tend to use the same mouse on both machines. And the same external HD. And the same webcam... etc., ad absurdum.
How many/which of those devices would have unique device identifiers such that the external observer could link the two identities?
Even if they had no internal drive, and only booted from live CD, would it be possible/likely that the motherboard chipset, RAM, screen, or CD drive itself could provide unique identification (assuming root privs, or their O/S's equivalent)?
What devices would allow a unique identifier to be set (other than mass storage; those obviously have state)? Is it possible I have a webcam which, unbeknownst to me, has some flash memory that an O/S could use to assign it a personal identifier?