When you access a website on your smartphone, your cellular carrier, network operator, and government all know you accessed that website. If you're in a country that blocks websites, like China, you may not even be able to access certain websites. Tor allows you to browse anonymously and bypass web censorship on your desktop. Orbot brings Tor to Android, so you can do the same from your smartphone.

Whether you're connected to a cellular data connection or Wi-Fi, Orbot works the same. Like the Tor browser bundle for PCs, it connects to the Tor network and allows you to browse the web anonymously.

How Anonymous is This, Really?

We've covered how Tor works in the past, so read our introduction to Tor and our explanation of how Tor's onion routing works for more in-depth information.

In a nutshell, Tor uses onion routing to disguise your location. When you access a website, you don't connect directly to that website -- you pass your encrypted data packet to an intermediary node, which encrypts the data and passes it to another node, and so on until it reaches the exit node. The exit node decrypts the data and sends it to the destination, which sees you as being at the exit node's location. The website talks to the exit node, which encrypts the data and sends it back through the nodes until it reaches you. Your data won't take the same path every time, but will go through different nodes.

In practice, it's very difficult for the end service to determine your location when you're using Tor to browse anonymously. It's also practically impossible for people monitoring your Internet connection to see what you're doing -- all they see is encrypted data. They may be able to deduce you're using Tor, but they won't be able to see what you're doing with Tor.

Why Would You Want to Do This?

If you're a dissident in a country like Iran, this means that the government can't track you down for posting information critical of them. It also lets you bypass web censorship and access websites, which is particularly useful in countries like China that censor the Internet. If you're in the US or anywhere else in the world, this means that your web browsing won't be linked to you and stored in a massive database thanks to PRISM and similar programs.

In the past, this functionality was restricted to people using Tor on their computers. However, you can now connect to Tor on Android so you can use Tor while mobile. In addition to preventing your cellular provider, network operator, and government from snooping on you, there are other advantages to having mobile Tor access. For example, you can use Twitter on Android over Tor. Some authoritarian governments have blocked access to Twitter so pro-democracy protests wouldn't be able to get the word out, but Twitter on Android could be set to use Tor. Twitter would remain accessible even if a government blocked access to it.

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Connect to Tor With Orbot

Orbot is the most important piece of this puzzle. This Android app connects to Tor and creates a local proxy that other apps on your smartphone can use, allowing them to connect through Tor.

Setting up Orbot is easy. Just install the app, open it, and walk through the setup wizard.

If you have root access on your smartphone, Orbot can function as a transparent proxy. In other words, it can automatically force all network traffic to go over Tor. If you do this route, bear in mind that some apps could leak your real IP address. To really browse anonymously, you should use a browser that's designed to hide your IP address. If you don't have root access, that's fine too -- you can still use Orbot with Orweb and other apps.

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Long-press the Orbot icon and Orbot will connect to the Tor network. The icon will glow green when connected to Tor.

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Browse Anonymously With Orweb

Editor's Note: since this article's publication in July 2013, it's been revealed that Orweb is vulnerable to real IP disclosure, and as such is not ideal for protecting your privacy. Tor's official blog confirms this.

Once Orbot is installed and running, you can use the Orweb browser to browse anonymously. Orweb is set up to function well with Orbot and Tor. For example, Orweb doesn't store any browsing history or other information about the websites you visit. Orweb also disables JavaScript and Flash by default, just as the Tor Browser Bundle does on the desktop. JavaScript and Flash could theoretically be used by a website to determine your smartphone's real IP address.

To launch Orweb from within Orbot, just tap the globe icon at the top of the Orbot screen. Orweb will open and display a message saying it's connected to Tor if everything is working properly. You can now use the Orweb browser to browse anonymously.

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Other Orbot-Enabled Apps

Orbot can also be used as a proxy for other apps. Any app that supports proxies could theoretically send its traffic over Orbot's Tor proxy. However, Orbot contains a list of other apps that can be configured to work with Orbot. For example, you can use Gibberbot [No Longer Available] to chat securely, the DuckDuckGo app to search over Tor, browse with Firefox for Android and the Proxy Mobile add-on, or set Twitter's proxy to "localhost" and port 8118.

If you have root access and set up a transparent proxy, other apps should theoretically work with Orbot -- but you're safest if you use apps specifically tested to work properly with Tor.

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Bear in mind that Tor is significantly slower than a standard connection for browsing, as the routing process adds some overhead. However, if you need to browse anonymously or bypass web censorship, this reduced speed is a small price to pay.

Do you have any other tips for using Tor on Android? Leave a comment below!

Image Credit: Tor diagram via Electronic Frontier Foundation