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Tor Browser prevents people from knowing the websites you visit. Some entities, such as your Internet Service Provider (ISP), may be able to see that you're using Tor, but they won't know where you're going when you do.

Generally it is impossible to have perfect anonymity, even with Tor. Though there are some things you can practice to improve your anonymity while using Tor and offline.

Use Tor Browser and software specifically configured for Tor

Tor does not protect all of your computer's Internet traffic when you run it. Tor only protects applications that are properly configured to send their Internet traffic through Tor.

Web browsing:

• Safe: Tor Browser
• Unsafe: Any other browser configured to use Tor as a proxy

File sharing:

• Safe: OnionShare
• Unsafe: BitTorrent over Tor

Control what information you provide through web forms

If you visit a website using Tor Browser, they don't know who you are or your true location. Unfortunately many sites ask for more personal information than they need through web forms. If you sign in to that website, they still don't know your location but they know who you are. Further, if you provide: name, email, address, phone number, or any other personal information, you are no longer anonymous to that website. The best defense is to be vigilant and extremely cautious when filling out web forms.

Don't torrent over Tor

Torrent file-sharing applications have been observed to ignore proxy settings and make direct connections even when they are told to use Tor. Even if your torrent application connects only through Tor, you will often send out your real IP address in the tracker GET request, because that's how torrents work. Not only do you deanonymize your torrent traffic and your other simultaneous Tor web traffic this way, you also slow down the entire Tor network for everyone else.

Don't enable or install browser plugins

Tor Browser will block browser plugins such as Flash, RealPlayer, Quicktime, and others: they can be manipulated into revealing your IP address. Similarly, we do not recommend installing additional addons or plugins into Tor Browser, as these may bypass Tor or otherwise harm your anonymity and privacy.

Use HTTPS versions of websites

Tor will encrypt your traffic to and within the Tor network, but the encryption of your traffic to the final destination website depends on that website. To help ensure private encryption to websites, Tor Browser includes HTTPS-Only Mode to force the use of HTTPS encryption with websites that support it. However, you should still watch the browser URL bar to ensure that websites you provide sensitive information to display a padlock or onion icon in the address bar, include https:// in the URL, and display the proper expected name for the website. Also see EFF's interactive graphic explaining how Tor and HTTPS relate.

Don't open documents downloaded through Tor while online

Tor Browser will warn you before automatically opening documents that are handled by external applications. DO NOT IGNORE THIS WARNING. You should be very careful when downloading documents via Tor (especially DOC and PDF files, unless you use the PDF viewer that's built into Tor Browser) as these documents can contain Internet resources that will be downloaded outside of Tor by the application that opens them. This will reveal your non-Tor IP address. If you must work with files downloaded via Tor, we strongly recommend either using a disconnected computer, or using dangerzone to create safe PDF files that you can open. Under no circumstances is it safe to use BitTorrent and Tor together, however.

Use bridges and/or find company

Tor tries to prevent attackers from learning what destination websites you connect to. However, by default, it does not prevent somebody watching your Internet traffic from learning that you're using Tor. If this matters to you, you can reduce this risk by configuring Tor to use a bridge rather than connecting directly to the Tor network. Ultimately the best protection is a social approach: the more Tor users there are near you and the more diverse their interests, the less dangerous it will be that you are one of them. Convince other people to use Tor, too!

Be smart and learn more. Understand what Tor does and does not offer. This list of pitfalls isn't complete, and we need your help identifying and documenting all the issues.

Tor Browser is currently available on Windows, Linux, macOS, and Android.

On Android, The Guardian Project also provides the Orbot app to route other apps on your Android device over the Tor network.

There is no official version of Tor Browser for iOS yet, as explained in this blog post. Our best available recommendation is Onion Browser.

It's strongly discouraged to install new add-ons in Tor Browser, because they can compromise your privacy and security.

Installing new add-ons may affect Tor Browser in unforeseen ways and potentially make your Tor Browser fingerprint unique. If your copy of Tor Browser has a unique fingerprint, your browsing activities can be deanonymized and tracked even though you are using Tor Browser.

Each browser's settings and features create what is called a "browser fingerprint". Most browsers inadvertently create a unique fingerprint for each user which can be tracked across the internet. Tor Browser is specifically engineered to have a nearly identical (we're not perfect!) fingerprint across its users. This means each Tor Browser user looks like many other Tor Browser users, making it difficult to track any individual user.

There's also a good chance a new add-on will increase the attack surface of Tor Browser. This may allow sensitive data to be leaked or allow an attacker to infect Tor Browser. The add-on itself could even be maliciously designed to spy on you.

Tor Browser already comes installed with one add-on — NoScript — and adding anything else could deanonymize you.

Want to learn more about browser fingerprinting? Here's an article on The Tor Blog all about it.

Generally speaking, we don't recommend using a VPN with Tor unless you're an advanced user who knows how to configure both in a way that doesn't compromise your privacy.

You can find more detailed information about Tor + VPN at our wiki.

Tor Browser can certainly help people access your website in places where it is blocked. Most of the time, simply downloading the Tor Browser and then using it to navigate to the blocked site will allow access. In places where there is heavy censorship we have a number of censorship circumvention options available, including pluggable transports.

For more information, please see the Tor Browser User Manual section on censorship circumvention.

Sure! We have a list of organizations that run Tor relays that are happy to turn your donations into better speed and anonymity for the Tor network.

These organizations are not the same as The Tor Project, Inc, but we consider that a good thing. They're run by nice people who are part of the Tor community.

Note that there can be a tradeoff here between anonymity and performance. The Tor network's anonymity comes in part from diversity, so if you are in a position to run your own relay, you will be improving Tor's anonymity more than by donating. At the same time though, economies of scale for bandwidth mean that combining many small donations into several larger relays is more efficient at improving network performance. Improving anonymity and improving performance are both worthwhile goals, so however you can help is great!

As mentioned above, it is possible for an observer who can view both you and either the destination website or your Tor exit node to correlate timings of your traffic as it enters the Tor network and also as it exits. Tor does not defend against such a threat model.

In a more limited sense, note that if a censor or law enforcement agency has the ability to obtain specific observation of parts of the network, it is possible for them to verify a suspicion that you talk regularly to your friend by observing traffic at both ends and correlating the timing of only that traffic. Again, this is only useful to verify that parties already suspected of communicating with one another are doing so. In most countries, the suspicion required to obtain a warrant already carries more weight than timing correlation would provide.

Furthermore, since Tor reuses circuits for multiple TCP connections, it is possible to associate non anonymous and anonymous traffic at a given exit node, so be careful about what applications you run concurrently over Tor. Perhaps even run separate Tor clients for these applications.

Internet communication is based on a store-and-forward model that can be understood in analogy to postal mail: Data is transmitted in blocks called IP datagrams or packets. Every packet includes a source IP address (of the sender) and a destination IP address (of the receiver), just as ordinary letters contain postal addresses of sender and receiver. The way from sender to receiver involves multiple hops of routers, where each router inspects the destination IP address and forwards the packet closer to its destination. Thus, every router between sender and receiver learns that the sender is communicating with the receiver. In particular, your local ISP is in the position to build a complete profile of your Internet usage. In addition, every server in the Internet that can see any of the packets can profile your behavior.

The aim of Tor is to improve your privacy by sending your traffic through a series of proxies. Your communication is encrypted in multiple layers and routed via multiple hops through the Tor network to the final receiver. More details on this process can be found in this visualization. Note that all your local ISP can observe now is that you are communicating with Tor nodes. Similarly, servers in the Internet just see that they are being contacted by Tor nodes.

Generally speaking, Tor aims to solve three privacy problems:

First, Tor prevents websites and other services from learning your location, which they can use to build databases about your habits and interests. With Tor, your Internet connections don't give you away by default -- now you can have the ability to choose, for each connection, how much information to reveal.

Second, Tor prevents people watching your traffic locally (such as your ISP or someone with access to your home wifi or router) from learning what information you're fetching and where you're fetching it from. It also stops them from deciding what you're allowed to learn and publish -- if you can get to any part of the Tor network, you can reach any site on the Internet.

Third, Tor routes your connection through more than one Tor relay so no single relay can learn what you're up to. Because these relays are run by different individuals or organizations, distributing trust provides more security than the old one hop proxy approach.

Note, however, that there are situations where Tor fails to solve these privacy problems entirely: see the entry below on remaining attacks.

The name "Tor" can refer to several different components.

Tor is a program you can run on your computer that helps keep you safe on the Internet. It protects you by bouncing your communications around a distributed network of relays run by volunteers all around the world: it prevents somebody watching your Internet connection from learning what sites you visit, and it prevents the sites you visit from learning your physical location. This set of volunteer relays is called the Tor network.

The way most people use Tor is with Tor Browser, which is a version of Firefox that fixes many privacy issues. You can read more about Tor on our about page.

The Tor Project is a non-profit (charity) organization that maintains and develops the Tor software.

Tor is the onion routing network. When we were starting the new next-generation design and implementation of onion routing in 2001-2002, we would tell people we were working on onion routing, and they would say "Neat. Which one?" Even if onion routing has become a standard household term, Tor was born out of the actual onion routing project run by the Naval Research Lab.

(It's also got a fine meaning in German and Turkish.)

Note: even though it originally came from an acronym, Tor is not spelled "TOR". Only the first letter is capitalized. In fact, we can usually spot people who haven't read any of our website (and have instead learned everything they know about Tor from news articles) by the fact that they spell it wrong.

No, it doesn't. You need to use a separate program that understands your application and protocol and knows how to clean or "scrub" the data it sends. Tor Browser tries to keep application-level data, like the user-agent string, uniform for all users. Tor Browser can't do anything about the text that you type into forms, though.

A typical proxy provider sets up a server somewhere on the Internet and allows you to use it to relay your traffic. This creates a simple, easy to maintain architecture. The users all enter and leave through the same server. The provider may charge for use of the proxy, or fund their costs through advertisements on the server. In the simplest configuration, you don't have to install anything. You just have to point your browser at their proxy server. Simple proxy providers are fine solutions if you do not want protections for your privacy and anonymity online and you trust the provider to not do bad things. Some simple proxy providers use SSL to secure your connection to them, which protects you against local eavesdroppers, such as those at a cafe with free wifi Internet.

Simple proxy providers also create a single point of failure. The provider knows both who you are and what you browse on the Internet. They can see your traffic as it passes through their server. In some cases, they can even see inside your encrypted traffic as they relay it to your banking site or to ecommerce stores. You have to trust the provider isn't watching your traffic, injecting their own advertisements into your traffic stream, or recording your personal details.

Tor passes your traffic through at least 3 different servers before sending it on to the destination. Because there's a separate layer of encryption for each of the three relays, somebody watching your Internet connection can't modify, or read, what you are sending into the Tor network. Your traffic is encrypted between the Tor client (on your computer) and where it pops out somewhere else in the world.

Doesn't the first server see who I am?

Possibly. A bad first of three servers can see encrypted Tor traffic coming from your computer. It still doesn't know who you are and what you are doing over Tor. It merely sees "This IP address is using Tor". You are still protected from this node figuring out both who you are and where you are going on the Internet.

Can't the third server see my traffic?

Possibly. A bad third of three servers can see the traffic you sent into Tor. It won't know who sent this traffic. If you're using encryption (like HTTPS), it will only know the destination. See this visualization of Tor and HTTPS to understand how Tor and HTTPS interact.

Yes.

The Tor software is free software. This means we give you the rights to redistribute the Tor software, either modified or unmodified, either for a fee or gratis. You don't have to ask us for specific permission.

However, if you want to redistribute the Tor software you must follow our LICENSE. Essentially this means that you need to include our LICENSE file along with whatever part of the Tor software you're distributing.

Most people who ask us this question don't want to distribute just the Tor software, though. They want to distribute Tor Browser. This includes Firefox Extended Support Release and the NoScript extension. You will need to follow the license for those programs as well. Both of those Firefox extensions are distributed under the GNU General Public License, while Firefox ESR is released under the Mozilla Public License. The simplest way to obey their licenses is to include the source code for these programs everywhere you include the bundles themselves.

Also, you should make sure not to confuse your readers about what Tor is, who makes it, and what properties it provides (and doesn't provide). See our trademark FAQ for details.

There are plenty of other programs you can use with Tor, but we haven't researched the application-level anonymity issues on all of them well enough to be able to recommend a safe configuration. Our wiki has a community-maintained list of instructions for Torifying specific applications. Please add to this list and help us keep it accurate!

Most people use Tor Browser, which includes everything you need to browse the web safely using Tor. Using Tor with other browsers is dangerous and not recommended.

There is absolutely no backdoor in Tor.

We know some smart lawyers who say that it is unlikely that anybody will try to make us add one in our jurisdiction (United States). If they do ask us, we will fight them, and (the lawyers say) probably win.

We will never put a backdoor in Tor. We think that putting a backdoor in Tor would be tremendously irresponsible to our users, and a bad precedent for security software in general. If we ever put a deliberate backdoor in our security software, it would ruin our professional reputation. Nobody would trust our software ever again - for excellent reasons!

But that said, there are still plenty of subtle attacks people might try. Somebody might impersonate us, or break into our computers, or something like that. Tor is open source, and you should always check the source (or at least the diffs since the last release) for suspicious things. If we (or the distributors that gave you Tor) don't give you access to the source code, that's a sure sign something funny might be going on. You should also check the PGP signatures on the releases, to make sure nobody messed with the distribution sites.

Also, there might be accidental bugs in Tor that could affect your anonymity. We periodically find and fix anonymity-related bugs, so make sure you keep your Tor versions up-to-date.

Tor (like all current practical low-latency anonymity designs) fails when the attacker can see both ends of the communications channel. For example, suppose the attacker controls or watches the Tor relay you choose to enter the network, and also controls or watches the website you visit. In this case, the research community knows no practical low-latency design that can reliably stop the attacker from correlating volume and timing information on the two sides.

So, what should we do? Suppose the attacker controls, or can observe, C relays. Suppose there are N relays total. If you select new entry and exit relays each time you use the network, the attacker will be able to correlate all traffic you send with probability around (c/n)^2. But profiling is, for most users, as bad as being traced all the time: they want to do something often without an attacker noticing, and the attacker noticing once is as bad as the attacker noticing more often. Thus, choosing many random entries and exits gives the user no chance of escaping profiling by this kind of attacker.

The solution is "entry guards": each Tor client selects a few relays at random to use as entry points, and uses only those relays for their first hop. If those relays are not controlled or observed, the attacker can't win, ever, and the user is secure. If those relays are observed or controlled by the attacker, the attacker sees a larger fraction of the user's traffic - but still the user is no more profiled than before. Thus, the user has some chance (on the order of (n-c)/n) of avoiding profiling, whereas they had none before.

You can read more at An Analysis of the Degradation of Anonymous Protocols, Defending Anonymous Communication Against Passive Logging Attacks, and especially Locating Hidden Servers.

Restricting your entry nodes may also help against attackers who want to run a few Tor nodes and easily enumerate all of the Tor user IP addresses. (Even though they can't learn what destinations the users are talking to, they still might be able to do bad things with just a list of users.) However, that feature won't really become useful until we move to a "directory guard" design as well.

Tor uses a variety of different keys, with three goals in mind: 1) encryption to ensure privacy of data within the Tor network, 2) authentication so clients know they're talking to the relays they meant to talk to, and 3) signatures to make sure all clients know the same set of relays.

Encryption: first, all connections in Tor use TLS link encryption, so observers can't look inside to see which circuit a given cell is intended for. Further, the Tor client establishes an ephemeral encryption key with each relay in the circuit; these extra layers of encryption mean that only the exit relay can read the cells. Both sides discard the circuit key when the circuit ends, so logging traffic and then breaking into the relay to discover the key won't work.

Authentication: Every Tor relay has a public decryption key called the "onion key". Each relay rotates its onion key every four weeks. When the Tor client establishes circuits, at each step it demands that the Tor relay prove knowledge of its onion key. That way the first node in the path can't just spoof the rest of the path. Because the Tor client chooses the path, it can make sure to get Tor's "distributed trust" property: no single relay in the path can know about both the client and what the client is doing.

Coordination: How do clients know what the relays are, and how do they know that they have the right keys for them? Each relay has a long-term public signing key called the "identity key". Each directory authority additionally has a "directory signing key". The directory authorities provide a signed list of all the known relays, and in that list are a set of certificates from each relay (self-signed by their identity key) specifying their keys, locations, exit policies, and so on. So unless the adversary can control a majority of the directory authorities (as of 2022 there are 8 directory authorities), they can't trick the Tor client into using other Tor relays.

How do clients know what the directory authorities are?

The Tor software comes with a built-in list of location and public key for each directory authority. So the only way to trick users into using a fake Tor network is to give them a specially modified version of the software.

How do users know they've got the right software?

When we distribute the source code or a package, we digitally sign it with GNU Privacy Guard. See the instructions on how to check Tor Browser's signature.

In order to be certain that it's really signed by us, you need to have met us in person and gotten a copy of our GPG key fingerprint, or you need to know somebody who has. If you're concerned about an attack on this level, we recommend you get involved with the security community and start meeting people.

Tor will reuse the same circuit for new TCP streams for 10 minutes, as long as the circuit is working fine. (If the circuit fails, Tor will switch to a new circuit immediately.)

But note that a single TCP stream (e.g. a long IRC connection) will stay on the same circuit forever. We don't rotate individual streams from one circuit to the next. Otherwise, an adversary with a partial view of the network would be given many chances over time to link you to your destination, rather than just one chance.

Digital signature is a process ensuring that a certain package was generated by its developers and has not been tampered with. Below we explain why it is important and how to verify that the Tor Browser you download is the one we have created and has not been modified by some attacker.

Each file on our download page is accompanied by a file labelled "signature" with the same name as the package and the extension ".asc". These .asc files are OpenPGP signatures. They allow you to verify the file you've downloaded is exactly the one that we intended you to get. This will vary by web browser, but generally you can download this file by right-clicking the "signature" link and selecting the "save file as" option.

For example, tor-browser-windows-x86_64-portable-13.0.1.exe is accompanied by tor-browser-windows-x86_64-portable-13.0.1.exe.asc. These are example file names and will not exactly match the file names that you download.

We now show how you can verify the downloaded file's digital signature on different operating systems. Please notice that a signature is dated the moment the package has been signed. Therefore every time a new file is uploaded a new signature is generated with a different date. As long as you have verified the signature you should not worry that the reported date may vary.

Installing GnuPG

First of all you need to have GnuPG installed before you can verify signatures.

For Windows users:

If you run Windows, download Gpg4win and run its installer.

In order to verify the signature you will need to type a few commands in windows command-line, cmd.exe.

For macOS users:

If you are using macOS, you can install GPGTools.

In order to verify the signature you will need to type a few commands in the Terminal (under "Applications").

For GNU/Linux users:

If you are using GNU/Linux, then you probably already have GnuPG in your system, as most GNU/Linux distributions come with it preinstalled.

In order to verify the signature you will need to type a few commands in a terminal window. How to do this will vary depending on your distribution.

Fetching the Tor Developers key

The Tor Browser team signs Tor Browser releases. Import the Tor Browser Developers signing key (0xEF6E286DDA85EA2A4BA7DE684E2C6E8793298290):

gpg --auto-key-locate nodefault,wkd --locate-keys [email protected]

This should show you something like:

gpg: key 4E2C6E8793298290: public key "Tor Browser Developers (signing key) <[email protected]>" imported
gpg: Total number processed: 1
gpg:               imported: 1
      EF6E286DDA85EA2A4BA7DE684E2C6E8793298290
uid           [ unknown] Tor Browser Developers (signing key) <[email protected]>

NOTE: Your output may deviate somewhat from the above (eg. expiration dates), however you should see the key correctly imported.

If you get an error message, something has gone wrong and you cannot continue until you've figured out why this didn't work. You might be able to import the key using the Workaround (using a public key) section instead.

After importing the key, you can save it to a file (identifying it by its fingerprint here):

gpg --output ./tor.keyring --export 0xEF6E286DDA85EA2A4BA7DE684E2C6E8793298290

This command results in the key being saved to a file found at the path ./tor.keyring, i.e. in the current directory. If ./tor.keyring doesn't exist after running this command, something has gone wrong and you cannot continue until you've figured out why this didn't work.

Verifying the signature

To verify the signature of the package you downloaded, you will need to download the corresponding ".asc" signature file as well as the installer file itself, and verify it with a command that asks GnuPG to verify the file that you downloaded.

The examples below assume that you downloaded these two files to your "Downloads" folder. Note that these commands use example file names and yours will be different: you will need to replace the example file names with exact names of the files you have downloaded.

For Windows users (change x86_64 to i686 if you have the 32-bit package):

gpgv --keyring .\tor.keyring Downloads\tor-browser-windows-x86_64-portable-13.0.1.exe.asc Downloads\tor-browser-windows-x86_64-portable-13.0.1.exe

For macOS users:

gpgv --keyring ./tor.keyring ~/Downloads/tor-browser-macos-13.0.1.dmg.asc ~/Downloads/tor-browser-macos-13.0.1.dmg

For GNU/Linux users (change x86_64 to i686 if you have the 32-bit package):

gpgv --keyring ./tor.keyring ~/Downloads/tor-browser-linux-x86_64-13.0.1.tar.xz.asc ~/Downloads/tor-browser-linux-x86_64-13.0.1.tar.xz

The result of the command should contain:

gpgv: Good signature from "Tor Browser Developers (signing key) <[email protected]>"

If you get error messages containing 'No such file or directory', either something went wrong with one of the previous steps, or you forgot that these commands use example file names and yours will be a little different.

Refreshing the PGP key

Run the following command to refresh the Tor Browser Developers signing key in your local keyring from the keyserver. This will also fetch the new subkeys.

gpg --refresh-keys EF6E286DDA85EA2A4BA7DE684E2C6E8793298290

Workaround (using a public key)

If you encounter errors you cannot fix, feel free to download and use this public key instead. Alternatively, you may use the following command:

curl -s https://openpgpkey.torproject.org/.well-known/openpgpkey/torproject.org/hu/kounek7zrdx745qydx6p59t9mqjpuhdf |gpg --import -

Tor Browser Developers key is also available on keys.openpgp.org and can be downloaded from https://keys.openpgp.org/vks/v1/by-fingerprint/EF6E286DDA85EA2A4BA7DE684E2C6E8793298290. If you're using MacOS or GNU/Linux, the key can also be fetched by running the following command:

gpg --keyserver keys.openpgp.org --search-keys EF6E286DDA85EA2A4BA7DE684E2C6E8793298290

You may also want to learn more about GnuPG.

Please see the Installation section in the Tor Browser Manual.

Please see the Uninstalling section in the Tor Browser Manual.

Please see the Updating section in the Tor Browser Manual.

The file you download and run prompts you for a destination. If you don't remember what this destination was, it's most likely your Downloads or Desktop folder.

The default setting in the Windows installer also creates a shortcut for you on your Desktop, though be aware that you may have accidentally deselected the option to create a shortcut.

If you can't find it in either of those folders, download it again and look for the prompt that asks you to choose a directory to download it in. Choose a directory location that you'll remember easily, and once the download finishes you should see a Tor Browser folder there.

Whenever we release a new stable version of Tor Browser, we write a blog post that details its new features and known issues. If you started having issues with your Tor Browser after an update, check out blog.torproject.org for a post on the most recent stable Tor Browser to see if your issue is listed. If your issue is not listed there, please check first Tor Browser's issue tracker and create a GitLab issue about what you're experiencing.

We want everyone to be able to enjoy Tor Browser in their own language. Tor Browser is now available in multiple languages, and we are working to add more.

Our current list of supported languages is:

Want to help us translate? Become a Tor translator!

You can also help us in testing the next languages we will release, by installing and testing Tor Browser Alpha releases.

No, Tor Browser is an open source software and it is free. Any browser forcing you to pay and is claiming to be Tor Browser is fake. To make sure you are downloading the right Tor Browser visit our download page. After downloading, you can make sure that you have the official version of Tor Browser by verifying the signature. If you are not able to access our website, then visit censorship section to get information about alternate way of downloading Tor Browser.

If you have paid for a fake app claiming to be Tor Browser, you can try to request a refund from the Apple or Play Store, or you can contact your bank to report a fraudulent transaction. We cannot refund you for a purchase made to another company.

You can report fake Tor Browsers on [email protected]

Tor Browser is currently available on Windows,