Misc

Tor relies on the support of users and volunteers around the world to help us improve our software and resources, so your feedback is extremely valuable to us (and to all Tor users).

Feedback template

When sending us feedback or reporting a bug, please include as many of these as possible:

  • OS you are using
  • Tor Browser version
  • Step by step of how you got to the issue, so we can reproduce it (e.g. I opened the browser, typed a url, clicked on (i) icon, then my browser crashed)
  • A screenshot of the problem
  • The log

How to Reach Us

There are several ways to reach us, so please use what works best for you.

Trac

You can file a ticket at https://trac.torproject.org. We track all Tor Browser 8 related issues with the ff60-esr keyword. Tickets related to our website should be added with the component "Webpages/Website."

Email

Send us an email at frontdesk at torproject.org

In the subject line of your email, please tell us what you're reporting. The more objective your subject line is (e.g. "Connection failure", "feedback on website", "feedback on Tor Browser, "I need a bridge"), the easier it will be for us to understand and follow up. Sometimes when we receive emails without subject lines, they're marked as spam and we don't see them.

For the fastest response, please write in English, Spanish, and/or Portuguese if you can. If none of these languages works for you, please write on any language you feel comfortable with, but keep in mind it will take us a bit longer to answer as we will need help with translation to understand it.

Blog post comments

You can always leave comments on the blog post related to the issue or feedback you want to report. If there is not a blog post related to your issue, please contact us another way.

IRC

You can find us in the #tor channel on OFTC to give us feedback or report bugs/issues. We may not respond right away, but we do check the backlog and will get back to you when we can.

Learn how to connect to OFTC servers.

Email Lists

For reporting issues or feedback using email lists, we recommend that you do on the one that is related to what you would like to report.

For feedback or issues related to Tor Browser use: tbb-bugs

For feedback or issues related to our websites, please use: ux

For feedback or issues related to Tor network or other projects developed by Tor please use: tor-dev

For feedback or issues related to running a Tor relay please use: tor-relays

For feedback on content related to Tor Browser Manual or Support website: tor-community-team

The community team has developed this Glossary of terms about and related to Tor

A

add-on, extension, or plugin

Add-ons, extensions, and plugins are components that can be added to web browsers to give them new features. Tor Browser comes with two add-ons installed: NoScript and HTTPS Everywhere. You should not install any additional add-ons to Tor Browser because that can compromise some of its privacy features.

antivirus software

An antivirus software is used to prevent, detect and remove malicious software. Antivirus software can interfere with Tor running on your computer. You may need to consult the documentation for your antivirus software if you do not know how to allow Tor.

App

A web application (web app), is an application which the client runs in a web browser. App can also refer to software that you install on mobile operating systems.

Atlas

Atlas is a web application to learn about currently running Tor relays.

B

bandwidth authority

To determine a relay's throughput, special relays called bandwidth authorities take periodic measurements of the relays in the consensus.

bridge

Like ordinary Tor relays, bridges are run by volunteers; unlike ordinary relays, however, they are not listed publicly, so an adversary cannot identify them easily. Pluggable transports are a type of bridge that help disguise the fact that you are using Tor.

bridge authority

A special-purpose relay that maintains the list of bridges.

browser fingerprinting

Fingerprinting is the process of collecting information about a device or service to make educated guesses about its identity or characteristics. Unique behavior or responses can be used to identify the device or service analyzed. Tor Browser prevents fingerprinting.

browsing history

A browser history is a record of requests made while using a web browser, and includes information like websites visited and when. Tor Browser deletes your browsing history after you close your session.

C

CAPTCHA

Captchas are a challenge-response test used in computing to determine whether the user is human or not. Tor users are often served captchas because Tor relays make so many requests that sometimes websites have a hard time determining whether or not those requests are coming from humans or from bots.

checksum

Checksums are hashvalues of files. If you have downloaded the software without errors, the given checksum and the checksum of your downloaded file will be identical.

circuit

A path through the Tor network built by clients consisting of randomly selected nodes. The circuit begins with either a bridge or a guard. Most circuits consist of three nodes - a guard or bridge, a middle relay, and an exit. Most onion services use six hops in a circuit (with the exception of single onion services), and never an exit node. You can view your current Tor circuit by clicking on the onion button in Tor Browser.

client

In Tor, a client is a node in the Tor network, typically running on behalf of one user, that routes application connections over a series of relays.

Compass

Compass is a web application to learn about currently running Tor relays in bulk.

consensus

In Tor terms, a single document compiled and voted on by the directory authorities once per hour, ensuring that all clients have the same information about the relays that make up the Tor network.

An HTTP cookie (also called web cookie, Internet cookie, browser cookie or simply cookie) is a small piece of data sent from a website and stored on the user's computer by the user's web browser while the user is browsing. Tor Browser does not store cookies.

cross-site scripting (XSS)

Cross-Site Scripting (XSS) allows an attacker to add malicious functionality or behavior to a website when they shouldn't have the ability to do so.

cryptographic signature

A cryptographic signature proves the authenticity of a message or file. It is created by the holder of the private portion of a public key cryptography key pair and can be verified by the corresponding public key. If you download software from torproject.org, you will find it as signature files (.asc). These are PGP signatures, so you can verify that the file you have downloaded is exactly the one that we intended you to get. For more information about how you can verify signatures, please see here.

D

Daemon

A daemon is a computer program that runs as a background process, rather than being under the direct control of a user.

directory authority

A special-purpose relay that maintains a list of currently-running relays and periodically publishes a consensus together with the other directory authorities.

E

encryption

The process of taking a piece of data and scrambling it into a secret code that can only be read by the intended recipient. Tor uses three layers of encryption in the Tor circuit; each relay decrypts one layer before passing the request on to the next relay.

end-to-end encrypted

Transmitted data which is encrypted from origin to destination is called end-to-end encrypted.

exit

The last relay in the Tor circuit which sends traffic out onto the public Internet. The service you are connecting to (website, chat service, email provider, etc..) will see the IP address of the exit.

ExoneraTor

The ExoneraTor service maintains a database of relay IP addresses that have been part of the Tor network. It answers the question whether there was a Tor relay running on a given IP address on a given date. This service is often useful when dealing with law enforcement.

F

Firefox

Mozilla Firefox is a free and open-source web browser developed by the Mozilla Foundation and its subsidiary, the Mozilla Corporation. Tor Browser is built from a modified version of Firefox ESR (Extended Support Release). Firefox is available for Windows, macOS and Linux operating systems, with its mobile version (fennec) available for Android.

firewall

A firewall is a network security system which monitors and controls the incoming and outgoing network traffic. This traffic filter is based on predetermined rules. A firewall typically establishes a barrier between a trusted, secure internal network and another outside network but it can also be used as a content filter in the sense of censorship. Sometimes people have trouble connecting to Tor because their firewall blocks Tor connections. You can reconfigure or disable your firewall and restart Tor to test this.

Flash Player

Flash Player is a browser pluginfor Internet applications to watch audio and video content. You should never enable Flash to run in Tor Browser as it is unsafe. Many services that use Flash also offer an HTML5 alternative, which should work in the Tor Browser.

fte

FTE (format-transforming encryption) is a pluggable transport that disguises Tor traffic as ordinary web (HTTP) traffic.

G

GetTor

It is a service that automatically responds to messages (Email, XMPP, Twitter) with links to the latest version of Tor Browser, hosted at a variety of locations, such as Dropbox, Google Drive and GitHub.

GSoC

The Tor Project participates in the Google Summer of Code, which is a summer program for university students.

guard

The first relay in the Tor circuit, unless using a bridge. When using a bridge, the bridge takes the place of the guard.

H

hash

A cryptographic hash value is the result of a mathematical algorithm that maps data to a bit string of a fixed size. It's designed as one-way-function which means the value is easy to calculate in one direction but infeasible to invert. Hash values serve to verify the integrity of data.

hidden services

Former name for "onion services", sometimes still in use in Tor documentation or communication.

hop

In Tor terms, a "hop" refers to traffic moving between relays in a circuit.

HTTP

The Hypertext Transfer Protocol (HTTP) is a channel used to send files and data between devices on a network. Originally used to transfer only web pages, it is now relied upon to deliver many forms of data and communication.

HTTPS

Hypertext Transfer Protocol Secure is the encrypted version of the HTTP channel used to transfer files and data between devices on a network.

HTTPS Everywhere

HTTPS Everywhere is a Firefox, Chrome, and Opera extension that makes HTTPS the default on websites that have set up HTTPS but have not made it the default. HTTPS Everywhere is installed in Tor Browser.

I

Internet Service Provider (ISP)

An Internet service provider (ISP) is an organization that provides services for accessing and using the Internet. When using Tor Browser, your ISP cannot see what websites you're visiting.

IP address

An Internet Protocol address (IP address) is a numerical (or alpha-numeric in the case of IPv6) label assigned to each device (e.g., computer, printer) participating in a computer network that uses the Internet Protocol for communication. The IP address is the location address of the device, similar to the addresses of physical locations. Tor Browser obscures your location by making it look like your traffic is coming from an IP address that is not your own.

J

JavaScript

JavaScript is a programming language that websites use to offer interactive elements such as video, animation, audio, and status timelines. Unfortunately, JavaScript can also enable attacks on the security of the web browser, which might lead to deanonymization. The NoScript extension in Tor Browser can be used to manage JavaScript on different websites.

K

L

little-t tor

"little-t tor" is one way of referring to tor the network daemon, as opposed to Tor Browser or Tor Project.

M

meek

These pluggable transports all make it look like you are browsing a major web site instead of using Tor. Meek-amazon makes it look like you are using Amazon Web Services; meek-azure makes it look like you are using a Microsoft web site; and meek-google makes it look like you are using Google search.

middle relay

The middle position in the Tor circuit. Non-exit relays can function as either a "middle" or a "guard" for different users.

N

New Identity

New Identity is a Tor Browser feature if you want to prevent your subsequent browser activity from being linkable to what you were doing before. Selecting it will close all your open tabs and windows, clear all private information such as cookies and browsing history, and use New Tor circuits for all connections. Tor Browser will warn you that all activity and downloads will be stopped, so take this into account before clicking “New Identity”. New Identity can also help if Tor Browser is having trouble connecting to a particular site, similarly to "New Tor Circuit for this Site".

New Tor Circuit for this Site

This option is useful if the exit you are using is unable to connect to the website you require, or is not loading it properly. Selecting it will cause the currently active tab or window to be reloaded over a new Tor circuit. Other open tabs and windows from the same website will use the new circuit as well once they are reloaded. This option does not clear any private information or unlink your activity, nor does it affect your current connections to other websites.

network censorship

Sometimes the direct access to the Tor network is blocked by your Internet Service Provider (ISP) or by a government. Tor Browser includes some circumvention tools for getting around these blocks, including bridges, pluggable transports, and GetTor.

NoScript

Tor Browser includes an add-on called NoScript, accessed through the “S” icon at the top-left of the window, which allows you to control the JavaScriptthat runs on individual web pages, or to block it entirely.

nyx

The anonymizing relay monitor (formerly arm, now nyx) is a terminal status monitor for Tor, intended for command-line usage. This is a tool for monitoring the core Tor process on a system, often useful for relay operators.

O

obfs3

Obfs3 is a pluggable transport that makes Tor traffic look random, so that it does not look like Tor or any other protocol. Obfs3 bridges will work in most places.

obfs4

Obfs4 is a pluggable transport that makes Tor traffic look random like obfs3, and also prevents censors from finding bridges by Internet scanning. Obfs4 bridges are less likely to be blocked than obfs3 bridges.

onion address

A standardized internet domain name used by onion services that ends in .onion and is designed to be self-authenticating.

OONI

OONI stands for "Open Observatory of Network Interference", it is a global observation network for detecting censorship, surveillance and traffic manipulation on the internet.

Onion Browser

An iOS app which is open source, uses Tor routing, and is developed by someone who works closely with the Tor Project. Learn more about Onion Browser

onion services

Onion services (formerly known as “hidden services”) are services (like websites) that are only accessible through the Tor network. Onion services offer advantages over ordinary services on the non-private web, including:

Onionoo

Onionoo is a web-based protocol to learn about currently running Tor relays and bridges. Onionoo provides the data for other applications and websites(compass, atlas, etc..) which in turn present Tor network status information to humans.

onionsite

An onionsite is another name for an onion service, but refers exclusively to websites. These websites use the .onion Top Level Domain (TLD).

onionspace

The set of available onion services. For example, you can say "my site is in onionspace" instead of "my site is in the Dark Web."

Operating System (OS)

The main system software that manages computer hardware and software resources and provides common services for computer programs. The most used desktop operating systems are Windows, macOS and Linux. Android and iOS are the dominant mobile operating systems.

Orbot

Orbot is a free app from The Guardian Project that empowers other apps on your device to use the internet more securely. Orbot uses Tor to encrypt your Internet traffic and hide it by bouncing through a series of computers around the world.

Orfox

Orfox is no longer maintained or supported.

To browse the web using Tor on Android, please use the supported Tor Browser for Android app developed by the Tor Project.

P

pluggable transports

Tools that Tor can use to disguise the traffic it sends out. This can be useful in situations where an Internet Service Provider (ISP) or other authority is actively blocking connections to the Tor network.

private key

The private portion of a public/private key pair. This is the key that must be kept private, and not disseminated to others.

proxy

A proxy is a middle man between a client (like a web browser) and a service (like a web server). Instead of connecting directly to the service, a client sends the message to the proxy. The proxy makes the request on behalf of the client, and passes the response back to the client. The service only communicates with and sees the proxy.

public key

The public portion of a public/private key pair. This is the key that can be disseminated to others.

public key cryptography

A public-key cryptography system uses pairs of mathematical keys. The public key can be disseminated widely while its belonging private key is known only by the owner of the key pair. Any person can encrypt a message using the public key of the receiver but only the receiver in possession of the private key is able to decrypt the message. Additionally, the private key can be used to create a signature to proof the identity of the creator of a message or other files. This signature can be verified by the public key.

Q

R

relay

A publicly-listed node in the Tor network that forwards traffic on behalf of clients, and that registers itself with the directory authorities.

S

Satori

It is an add-on for the Chrome or Chromium browsers that allows you to download several security and privacy programs, including Tor Browser, from different sources. You can Install Satori from the Chrome Web Store.

scramblesuit

Scramblesuit is similar to obfs4 but has a different set of bridges.

script

Elements used for offering dynamic/interactive content via websites.

self-authenticating address

The specialized address format of onion addresses is self-authenticating. The format automatically guarantees that the onion address is bound to the key used to protect connections to the onionsite. Ordinary internet domain names require site owners to trust and be approved by a Certificate Authority (CA) for this binding, and they are subject to hijack by the CA and typically by many other parties as well.

server

A device on a network which offers a service, such as file and web page storage, email or chat.

session

A session refers to a conversation between two devices communicating on a network. Using Tor Browser means that your session data will be wiped when you close the web browser.

single onion service

A single onion service is an onion service that can be configured for services that do not require anonymity, but want to offer it for clients connecting to their service. Single onion services use only three hops in the circuit rather than the typical six hops for onion services.

Stem

Stem is a Python (programming language) controller library for core Tor. If you want to control core Tor with python, this is for you.

Sybil attack

The Sybil attack in computer security is an attack wherein a reputation system is subverted by creating a large number of identities, and using them to gain a disproportionately large influence in the network.

T

Tails

Tails is a "live" operating system, that you can start on almost any computer from a DVD, USB stick, or SD card. It aims to preserve your privacy and anonymity. Learn more about Tails.

The Tor Project

The Tor Project can refer to either The Tor Project Inc, a 501(c)3 US nonprofit responsible for maintaining the Tor software, or the Tor Project community made up of thousands of volunteers from all over the world who help create Tor.

third-party tracking

Most websites use numerous third-party services, including advertising and analytics trackers, which collect data about your IP address, web browser, system and your browsing behavior itself, all of which can link your activity across different sites. Tor Browser prevents a lot of this activity from happening.

Tor / Tor network/ Core Tor

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. Sometimes the software associated with this network is called Core Tor, and sometimes "little-t tor". The way most people use Tor is with Tor Browser which is a version of Firefox that fixes many privacy issues.

Tor Browser

Tor Browser uses the Tor network to protect your privacy and anonymity. Your internet activity, including the names and addresses of the websites you visit, will be hidden from your Internet Service Provider (ISP) and from anyone watching your connection locally. The operators of the websites and services that you use, and anyone watching them, will see a connection coming from the Tor network instead of your real Internet (IP) address, and will not know who you are unless you explicitly identify yourself. In addition, Tor Browser is designed to prevent websites from “fingerprinting” or identifying you based on your browser configuration. By default, Tor Browser does not keep any browsing history. Cookies are only valid for a single session (until Tor Browser is exited or a New Identity is requested).

Tor Launcher

When you run Tor Browser for the first time, you see the Tor Launcher window. It offers you the option to connect directly to the Tor network, or to configure Tor Browser for your connection. In the second case Tor Launcher will take you through a series of configuration options.

Tor log

"Tor log" is an automatically-generated list of Tor’s activity that can help diagnose problems. When something goes wrong with Tor, you may see an option with the error message to "copy Tor log to clipboard". If you don't see this option and you have Tor Browser open, you can navigate to the Torbutton (on the top left of the browser, to the left of the URL bar). Click the Tor button, then open Tor Network Settings. You should see an option at the bottom to copy the log to your clipboard, which you can then paste to a document to show whoever is helping you troubleshoot.

Tor Messenger

Tor Messenger was a cross-platform chat program that aimed to be secure by default and send all of its traffic over Tor. Tor Messenger is not in development anymore. It supported Jabber (XMPP), IRC, Google Talk, Facebook Chat, Twitter, Yahoo, and others; enabled Off-the-Record (OTR) Messaging automatically; and had an easy-to-use graphical user interface localized into multiple languages.

TorBirdy

This extension configures Thunderbird to make connections over Tor.

Torbutton

A button marked by a little green onion to the left of the URL bar. Its menu offers you "New Identity", "Security Settings..." and "Check for Tor Browser Update..." options.

torrc

The core Tor configuration file.

Torsocks

Torsocks allows you to use many applications in a safer way with Tor. It ensures that DNS requests are handled safely and explicitly rejects any traffic other than TCP from the application you're using.

Tor2Web

Tor2web is a project to let users access onion services without using the Tor Browser. NOTE: This is not as safe as connecting to the onion services via Tor Browser, and will remove all Tor-related protections the client would otherwise have.

TPI

TPI is an acronym for The Tor Project, Inc.

tpo

People on IRC often use tpo to abbreviate torproject.org when writing hostnames. For example, trac.tpo is an abbreviation for trac.torproject.org.

traffic

Traffic is the data sent and received by clients and servers.

U

V

W

Web Browser

A web browser (commonly referred to as a browser) is a software application for retrieving, presenting, and traversing information resources on the World Wide Web. Major web browsers include Firefox, Chrome, Internet Explorer, and Safari.

website mirror

A website mirror is an one-to-one copy of a website which you can find under other web addresses. A current list of torproject.org mirrors is available at https://www.torproject.org/getinvolved/mirrors.html.en.

X

Y

Z

There is nothing the Tor developers can do to trace Tor users. The same protections that keep bad people from breaking Tor's anonymity also prevent us from tracking users.

No, the Tor Project does not offer hosting services.

Right now the path length is hard-coded at 3 plus the number of nodes in your path that are sensitive. That is, in normal cases it's 3, but for example if you're accessing an onion service or a ".exit" address it could be more.

We don't want to encourage people to use paths longer than this as it increases load on the network without (as far as we can tell) providing any more security. Also, using paths longer than 3 could harm anonymity, first because it makesdenial of security attacks easier, and second because it could act as an identifier if only a small number of users have the same path length as you.

Many exit nodes are configured to block certain types of file sharing traffic, such as BitTorrent. BitTorrent in specific is not anonymous over Tor.

For sharing files over Tor, OnionShare is a good option.

Thank you for your support! You can find more information about donating on our donor FAQ.

Tor is designed to defend human rights and privacy by preventing anyone from censoring things, even us. We hate that there are some people who use Tor to do terrible things, but we can't do anything to get rid of them without also undermining the human rights activists, journalists, abuse survivors, and other people who use Tor for good things. If we wanted to block certain people from using Tor, we'd basically be adding a backdoor to the software, which would open up our vulnerable users to attacks from bad regimes and other adversaries.

Tor is funded by a number of different sponsors including US federal agencies, private foundations, and individual donors. Check out a list of all our sponsors and a series of blog posts on our financial reports.

We feel that talking openly about our sponsors and funding model is the best way to maintain trust with our community. We are always seeking more diversity in our funding sources, especially from foundations and individuals.

We do not recommend using Tor with BitTorrent. For further details, please see our blog post on the subject.

We are so sorry, but you have been infected with malware. The Tor Project did not create this malware. The malware authors are asking you to download Tor Browser presumably to contact them anonymously with the ransom they're demanding from you.

If this is your first introduction to Tor Browser, we understand that you might think we're bad people who enable even worse people.

But please consider that our software is used every day for a wide variety of purposes by human rights activists, journalists, domestic violence survivors, whistleblowers, law enforcement officers, and many others. Unfortunately, the protection that our software can provide to these groups of people can also be abused by criminals and malware authors. The Tor Project does not support or condone the use of our software for malicious purposes.

Tor doesn't keep any logs that could identify a particular user. We do take some safe measurements of how the network functions, which you can check out at Tor Metrics.

No, we don't provide any online services. A list of all of our software projects can be found on our projects page.

Vidalia is no longer maintained or supported. A large portion of the features Vidalia offered have now been integrated into Tor Browser itself.