Using the Tor Browser, one thing I've noticed while looking at the EFF's Panopticon browser fingerprinting tool is that the screen size reported matches the dimensions of the browser window. While this makes sense in that it is ephemeral, it also results in some unique screen resolutions that are easily identifiable.

So, a couple of questions:

a) Is there a tool to resize the Tor Browser to a specified screen resolution?

b) Is there a way to force the Tor Browser to return a common screen resolution, regardless of actual browser size ?


For Windows (the OP does not specify an OS), I've used this shareware utility for years -- can't vouch for it beyond saying I've never had any problems (technical nor malware-related) with it in 5+ years of daily use on 4 Windows boxes, including Windows 7 (don't know about Win 8):


A right-click anywhere on a window frame (any window, not just a browser) tells you the current window size; you can drag any edge or corner and see real-time size while resizing in 1 or 2 dimensions; and you can define and give names to arbitrary custom window sizes that can be picked from a menu on the same right-click pop-up.

So it answers both requests (a) and (b) from the OP: a moment with Panopticlick to get your reported screen size, compare those with the Sizer-reported frame size, do a bit of subtraction and addition to figure out the dimensions of your borders and other chrome, and voila! you can define a custom size to mimic a standard size.


So far the best I've found is a firefox plugin, but it is of unknown origin and maybe not trustworthy.

  • Firesizer - this provides details on current screen size but I have no found a way to set the size)

I also stumbled across Stop Fingerprinting, which I had high hopes for but apparently it is just gathering data for another site (apparently INRIA) and provides no functionality or protection. In fact, this is probably a deanonymization threat and should not be used with Tor at all.

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