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(2010-06-17) The future of anonymizers

As you probably know, only crooks encrypt their network traffic. If you haven’t done anything wrong, you have nothing to hide from anyone… Ever. It’s not like anyone else would ever disagree on what is ok or that someone might use things out of context to discredit you. I mean you gotta trust your friends, neighbors and the government.

But enough about the fictitious world found in clueless people’s arguments and let’s head back to reality. Being anonymous is a growing “hobby” for lots of people like you and me and dissidents who really want to avoid getting into trouble with the government. A hard learned lesson is how little protection you get from services promising total transparency.

The TOR network embassy scandal of 2007 proves this. 1] The principle of TOR is called Onion routing 2]. The idea is that every Onion router can only know about the last node the packet came from and the next node to which it must sent. But just because the government can’t see you, doesn’t mean the operators on the nodes themselves are blind as well. What happened was that Dan Egerstad, a Swedish security consultant, running an exit node in the TOR network started “sniffing” for clear text passwords going through the service. He then leaked the results.

A variant of Onion routing, known as “Garlic Routing”, tries to solve the problem of eavesdropping. The big change is that your traffic is split up over several routers, and transmitted in random bursts. An evil exit node will only get a scatter of mixed messages from a lot of different people and will have a much harder time trying to analyze the traffic patterns or reading the content.

Another thing people forget is that the size of the encrypted traffic matches the size of non-encrypted traffic. If you download a page on website that consists of 12 gif-images and one html file, the file size and number of files transferred can be measured even when encrypted. The size and amount of files creates a fairly unique signature that may be used to deanonymize your surfing habits. The garlic routing concept I2P 3] tries to solve this by padding the length of the packets. It makes it very hard to infer anything from the measurements of the data streams.

To sum it up, if you intend to use an anonymization service, know who you’re hiding from and remember that you can’t trust the service. Don’t ever send credentials in clear text over an anonymizer, if you can’t handle someone reading them. Adding end-to-end encryption will make exploitation of this by rogue nodes harder.

I don’t care for TOR or any I2P networks, as I believe nosy neighbors or idiots running Aircrack being a more likely threat than the Swedish government. I settle for a fairly useless service called dold.se, well knowing it’s only as good as IDG’s reputation. Remember it terminates in Sweden, so FRA will be able to read the traffic anyway. And if the raid of Bahnhof in 2005 is any indicator, it’s not that much protection at all. 4)

1)
http://www.theregister.co.uk/2007/09/10/misuse_of_tor_led_to_embassy_password_breach/
2)
http://www.onion-router.net/
3)
http://en.wikipedia.org/wiki/I2P
4)
http://www.theregister.co.uk/2005/03/14/bahnhof_bust/

(Originally written 2010-01-18)

Posted: 2010-06-17 by Erik Zalitis
Changed: 2010-06-17 by Erik Zalitis

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