Tor Browser is a privacy-focused browser that lets you navigate the internet without anyone monitoring your activity or identifying you. It relies on the Tor anonymity network to route your internet traffic through multiple random servers before connecting to your desired website or service.

You can download Tor Browser here(new window).

This article explains more about Tor, how Tor Browser works, why you might use it, and some of the browser’s limitations. The app is free to download and use as a service of The Tor Project, a nonprofit that promotes human rights through privacy technologies.

What is Tor Browser?

How does Tor Browser work?

A few limitations to consider

Why use Tor Browser?

Using Tor Browser to access Proton

What is Tor Browser?

Tor Browser is similar to other browsers like Firefox or Chrome that let you visit websites on the internet. When you enter a URL for a website, the browser looks up the location of that website on the internet and downloads the site content. 

But Tor Browser is unique because it has built-in privacy and anonymity safeguards. It also lets you access websites on the dark web that other browsers can’t take you to (more on that below). 

Tor browser has three important privacy features:

1. It blocks surveillance of your browsing activity

With a normal browser, at least one or two observers can potentially keep track of the websites you visit: your internet service provider and possibly your WiFi administrator (if you’re at work or a coffee shop, for example). While TLS encryption(new window) prevents them from seeing the information you provide on those websites, they can still see what websites you visit and when. 

Tor Browser prevents this. The only thing your ISP and anyone else on the local internet can see is that you’re connected to Tor.

2. It prevents websites from identifying you

The websites you visit can typically see your IP address. Website operators can use this information to see your general location and potentially to identify you. This piece of information is a critical part of the surveillance economy (along with cookies and other trackers) that give marketers the ability to profile and target you.

When you use Tor Browser, websites can only see the IP address of the last node your internet traffic passed through in the Tor network. 

3. It clears tracking cookies

Another way websites can track you is by planting cookies on your browser. These are small files that log your activities on the internet. Some cookies are useful, such as those that remember your website preferences or the items in your shopping cart. Tracking cookies, which monitor your behavior across other websites, are a threat to your privacy.

Tor Browser scrubs cookies after each session by default.

How does Tor Browser work?

By default, Tor Browser connects your internet traffic to three random relays (also called nodes) in the Tor network before connecting you to the website you want to access. Tor also uses three layers of encryption that get removed with each node — the so-called onion routing from which Tor (“The Onion Router”) derives its name.

How Tor works

The Tor Project depends on thousands of volunteers to operate relays in its network. Each of these nodes can only see the nodes behind them and in front of them. 

Therefore, only the entry node can see your computer’s IP address, but it can’t see what website you’re connecting to. The exit node can only see the IP address of the middle node, but it does know what website you’re connecting to. And the website can only see the exit node as the source of its traffic.

During the leap from the last node to the website, your web traffic is not encrypted and relies on the website’s HTTPS(new window) to protect your data. But by then your traffic looks pretty much like all the other traffic exiting the Tor network. It’s extremely difficult to identify you as the source. (Though not impossible — see the next section.)

A few limitations to consider

Tor Browser isn’t a magic invisibility cloak. You can’t use it and expect everything you do online to remain anonymous. In fact, maintaining anonymity on Tor requires a good bit of vigilance on your part.

Here are some limitations of Tor Browser you should keep in mind to increase your privacy:

  • Information you give to websites can de-anonymize you. For example, if you log in to your Google account in Tor Browser, Google will know who you are. Any information you submit in forms could also identify you.
  • A sophisticated attacker can monitor Tor network traffic. Governments may try to identify specific Tor users by watching internet traffic for patterns. This is expensive and probably not something most people need to worry about. Learn more about Tor vulnerabilities.
  • Attackers and governments can compromise Tor nodes and monitor traffic. If an attacker can see the entry and/or exit nodes, they have a good chance of identifying you. But the odds of this are very low(new window).
  • File-sharing services aren’t very compatible with Tor. The nature of BitTorrent and other file-sharing sites makes it difficult to stay anonymous. It’s also extremely slow to torrent over Tor.
  • Tor Browser is slower than other browsers. Because of the extra encryption involved in onion routing and because your connection is often routed across the globe to reach the volunteer-administered Tor nodes, Tor Browser is slower than browsers optimized for speed.
  • Tor Browser only encrypts your browser traffic. Other internet traffic on your device, including your apps, will not be encrypted in the Tor network and could be used to identify you. If you’re concerned about that, Tor also offers an operating system called Tails(new window) that will encrypt all your traffic.

Why use Tor Browser?

The internet is full of marketing trackers, malware, and government surveillance. In some countries, whole parts of the internet are off-limits because of censorship. Tor Browser addresses all these problems.

Here are some of the main use cases:

  • You don’t want websites to be able to track you. Tor Browser includes features that scrub cookies after each web session and clears your browsing history automatically. It also makes all traffic exiting the Tor network look the same, so device fingerprinting(new window) is much more difficult.
  • You want to access censored content. A lot of the censorship online is fairly easy to circumvent with a VPN or by using Tor because it interferes with domain names at the level of your internet service provider. When you connect to the Tor network, you prevent your internet service provider from seeing your web traffic and bypass the block.
  • You don’t want anyone to see your online activity. Tor encrypts your web traffic between your local network and the Tor entry node, preventing your internet service provider and/or your network administrator from monitoring your behavior. Websites can’t see the source of your traffic beyond the Tor exit node. And each of the three random nodes within the network can only potentially see your IP address or the IP address of the site you’re visiting, but not both. Therefore, when used properly, Tor prevents anyone from associating you with your online activity.
  • You want to access onion sites. Tor offers Onion Services, which are websites that only exist on the Tor network. Sometimes called the dark web, these sites are almost impossible to censor. While some content on the dark web lives up to its seedy reputation, there are also many useful onion sites, including Proton. We’ve compiled a list of the best onion sites you can check out. You can only connect to onion sites through Tor.

If you’re familiar with VPN services, you might notice similarities between what Tor and VPN both offer. Each lets you unblock websites and prevents them and your ISP from watching your activity. The biggest difference is that a VPN can see your online activity (which is why it’s important to choose a VPN you trust). Tor, meanwhile, is a network in which no two nodes will ever know both your identity and your activity. 

When is it better to use a VPN rather than Tor? The clearest use cases are when you want to access blocked content on the internet where performance is also a priority, such as video streaming sites. Additionally, Tor Browser only protects your web traffic, while a VPN protects all the internet traffic on your device.

A good no-logs VPN is adequate to protect most people’s privacy in most situations. Proton VPN also allows you to access onion sites with our Tor over VPN feature.

Using Tor Browser to access Proton

Some countries see online privacy as a threat and try to block services like Proton that make it possible. Tor is a vital technology in the fight against censorship and surveillance. But it can only exist with the support of savvy volunteers to operate the Tor relays and donations in support of The Tor Project. 

This is why Proton is a Green Onion Member(new window) of Tor’s sustaining membership program.

And it’s also why we operate and maintain an official Proton onion site(new window). Even if the government blocks Proton where you are, you can still access your Proton Account through our onion site.
We recently updated our onion site(new window) so you can use Proton Mail, Proton Calendar, and Proton Drive or sign up for a new account via Tor. You can access our Tor site through Tor Browser(new window) or by connecting to a Proton VPN Tor server.

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