Friday, 11 April 2008

Onion Routing

I was reading up on Onion Routing the other day and thought that I'd try it out to see if a) it was any good and b) how useful it might be. Before I go any further, perhaps I should explain that I'm not one of the Tin Foil Hat brigade and, frankly, don't care who knows where I visit or what I do when I'm on-line. Be that as it may, my curiosity was piqued and I installed Tor and Privoxy on my laptop to give it a whirl.

A note for Firefox 3 Beta users: at the time of writing, I noticed that a few of the Tor plug-ins wouldn't install for version 3 but FoxyProxy worked just fine.

Having got it all installed and configured, I set about testing it all. As far as I could tell, it did a bloody good job at making me anonymous and my exit node seemed to change approximately every 10 minutes. The performance through some nodes was pretty poor (I was not surprised by this and was expecting it, to be honest - some of the nodes are run by enthusiasts and are very far away).

This made using sites like Google interesting: one minute they thought I was German, the next minute Belgian, the owner of a compromised computer, Chinese and so on. Surfing from behind The Great Fire Wall of China was, erm, interesting and that got me really thinking. How often would this happen? This was a big disadvantage to the whole experience and made me think that Onion Routing should only be used on a need to use basis. (If I'm stating the obvious, so be it).

To surmise, I think that it should only be switched on if there's a desperate need to visit somewhere anonymously.

In order to get a feel for how annoying it could be, I generated a script to monitor the GEO-IP of whatever exit nodes were being used over a period of time so that I could determine how many of the exit nodes were very distant or censored and get a feel for how the surfing experience would be diminished. The results of my labours are here.

This is the code that I wrote to do the analysis and a pie chart of the outcomes is below (you have to have pie charts, you know).


Tor Exit Nodes by Country

Over the 18 hours, 78 unique IP addresses were used as Tor Exit Nodes though I'm not going to publish them here :-)

As an ironic footnote, I should mention that I'm based in .uk. Only one, yes, one exit node was GB. Of course, none of this takes into account of which territories I am passing through during a particular onion session.

3 comments:

GrimlyCurmudgeon said...

Interesting, ta.

Tosspot said...

Useful. See also tork http://anonymityanywhere.com/tork/

prawn said...

Cheers for the comments chaps -- and for the reminder that I haven't blogged anything for a while :-)