The Tor Bundle
I've been using the Tor Bundle on OS X for about a week, and now it's my main browser (it's a FireFox clone).
Here's why Tor and how it works:
Using Tor protects you against a common form of Internet surveillance known as "traffic analysis." Traffic analysis can be used to infer who is talking to whom over a public network. Knowing the source and destination of your Internet traffic allows others to track your behavior and interests. This can impact your checkbook if, for example, an e-commerce site uses price discrimination based on your country or institution of origin.
A generalization of what some online airline ticket sellers do: Figuring OS X people are above average income -- BWA-HA-HA-HA!!! -- they will display higher prices than for Windows users.
It can even threaten your job and physical safety by revealing who and where you are. For example, if you're travelling abroad and you connect to your employer's computers to check or send mail, you can inadvertently reveal your national origin and professional affiliation to anyone observing the network, even if the connection is encrypted.
Tor helps to reduce the risks of both simple and sophisticated traffic analysis by distributing your transactions over several places on the Internet, so no single point can link you to your destination. The idea is similar to using a twisty, hard-to-follow route in order to throw off somebody who is tailing you — and then periodically erasing your footprints. Instead of taking a direct route from source to destination, data packets on the Tor network take a random pathway through several relays that cover your tracks so no observer at any single point can tell where the data came from or where it's going.
To create a private network pathway with Tor, the user's software or client incrementally builds a circuit of encrypted connections through relays on the network. The circuit is extended one hop at a time, and each relay along the way knows only which relay gave it data and which relay it is giving data to. No individual relay ever knows the complete path that a data packet has taken. The client negotiates a separate set of encryption keys for each hop along the circuit to ensure that each hop can't trace these connections as they pass through.
The first time I tried the Tor browser, maybe two year ago, it was just too slow. Now it isn't, at least for my needs (mostly reading, and not video or games). I guess that's because there are many more Tor relays available to bounce my URL requests through to hide the IP address I'm coming from.
- Google results are often not in English (if the final bounce is in Russia, say);
- Yahoo and Google sometimes want Captchas
- Corrrente had issues with some IP addresses until I tinkered with some modules;
- Some logins (like the Financial Times, or the New York Times) are unhappy
But, in general, I'm very happy and feel more (not perfectly) secure. I still keep other browsers (especially Aviator) around, but mainly, I'm using Tor. After all, why should I be giving my browsing data away to just anyone?
NOTE One more disadvantage: The Tor documentation explains that the Tor Browser will let you install plug-ins, but that a profile of plug-ins can be used as a way to help identify you. So I keep the other browsers around for some special purposes.