July 08, 2013, 6:45 PM — About a week ago I posted an item about the NinjaStik, a USB thumb drive that uses The Onion Routing (Tor) to anonymize your Web surfing and otherwise protect you from the prying eyes of scary Three Letter Agencies. This post prompted the following comment from a (naturally) anonymous reader:
tor is not privacy. you have no idea who is running that node and they can collect your data quite easily. very dangerous article
In the past I have been accused of being a danger to myself and others, most often by my wife and typically while using power tools. But this is the first time I’ve been accused of writing anything dangerous. So it gave me pause. Is Tor actually unsafe? In other words, is that Tor node you just logged on to really being operated by the NSA? Am I just another unwitting tool of the Industrial Surveillance Complex?
Without getting excessively geeky and/or making my brain hurt, I decided to try and find out. Here’s my Tor Anonymity for Dummies explanation (which I’m sure some reader will write to tell me is totally wrong):
When you use Tor, it routes your traffic through three nodes, aka machines on the Tor network, chosen at random. The entry node knows your IP address but encrypts it and passes it on to the second node; the second node only knows the IP address of the first node, and passes it on to a third machine. The last machine in the chain (aka the exit node) decrypts the data, so it knows where to send your request, but it only knows the IP address of the last machine it touched, not the original IP address where the request was made.
This is why Tor is called The Onion Routing – it forces all traffic to pass through multiple layers.
Are there spooks operating Tor nodes? We can’t say for sure, but let’s assume they are.
If spook organization A happens to operate both the entry node and the exit node for your traffic, they could unravel your identity fairly easily. I don’t know what the odds are of that happening, but I can’t imagine they’re very high. And if you’re a particular kind of geek, you can manually select both the entry and exit nodes to pick ones you know are secure (or, at least, you think you know are secure).
If you are using Tor to send unencrypted information about yourself – like your email address or password – it could be captured by the spook’s exit node. The solution there is to use an encrypted connection.