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Re: [tor-talk] Tor browser can be fingerprinted

> Mike Perry:
> > 
> > So this means that if you resize your browser, you also get a
> > totally different display fingerprint. However, if you resize it to
> > something weird, and continue to use that weird size for a while,
> > all of that activity is highly linkable to advertisers until you
> > resize again.
> > 
> Equally, 'if you maximize your browser (or your browser maximizes
> itself automatically, as Tor Browser does when I click 'New Identity),
> and your screen is some weird size, all of your activity is highly
> linkable to advertisers until you get a new screen'?

Your Tor Browser should *not* be maximizing itself during New Identity.
It should be setting its content window to a 200x100 multiple.

I've never seen one maximize for that step. Does that always happen for
you? Sounds like a bug caused by something about your setup. Does it
happen with a fresh bundle in a new directory? Do you mind sharing your
monitor resolution?
> Also, 'if you want to do something unlinkable, pick a weird screen
> size and then change it after you finish doing it?'

Maybe. It depends on if you resizing the window is actually as "random"
as you think it is. If you keep doing that, and you're one of the few
people who does, you might stand out over time?  On the other hand, it
seems like a tricky algorithm for an advertiser-class adversary to
write, and for little economic gain since it is rare behavior.

However, if your adversary includes people with access to raw
advertising logs, that may be a different matter. My guess is
capital-t-They wouldn't bother with that vector though. Too expensive
for too little information.

So on balance, I think it's probably a decent thing to do for that odd
website account you don't want linked to anything else?

> I get that this is difficult to avoid. Just trying to clarify.


Mike Perry

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