What Is Tor? How Tor Browser Protects Your Anonymity

Additional resource for the lesson “Introduction to TOR” — Online Anonymity course

What is Tor? It is a free network, run by volunteers, that carries your connection through three relays so that no single point along the way knows both who you are and which site you are visiting. Tor Browser is the usual way to use it. This resource explains how it works in plain words, who uses it and why, and what it leaves for you to look after.

A. Why this matters

In this course, privacy is deciding what others know about you; anonymity is being able to act without what you do being linked back to who you are. Earlier resources looked at the links: your IP address, cookies, sign-ins, the details your browser shares. Tor is one of the few tools designed from the start to loosen several of those links at once.

You may have heard Tor mentioned only in stories about the “dark web”. That is a narrow picture of a tool people use for ordinary reasons: to read without being profiled, or to reach sites blocked where they live. Choosing it is a matter of proportion, not of secrecy.

A note on the name: the Tor Project writes “Tor”, with only the first letter capitalised, and so does this resource.

What the sources say

The Tor Project, the non-profit that develops the software, describes Tor as a way of “bouncing your communications around a distributed network of relays run by volunteers all around the world”. This, it explains, “prevents somebody watching your Internet connection from learning what sites you visit” and “prevents the sites you visit from learning your physical location”. Its history page says the network now has “thousands of relays run by volunteers and millions of users worldwide.”

The Electronic Frontier Foundation (EFF), a digital rights organisation, calls Tor “a volunteer-run service that provides both privacy and anonymity online”, working by “sending your traffic through three hops, also called Tor relays”. Its guide, last reviewed in January 2025, is equally clear about the trade-offs: browsing “is much slower over Tor”, and “anyone who can see your network activity can also see that you’re using Tor.”

In Europe, the Austrian Science Fund (FWF) funded a research project at SBA Research on the future of online anonymity. Its summary describes Tor as “the go-to software for people seeking to disconnect their online persona(e) from their real identity”: linkability in a single line.

B. Key concepts: what is Tor, piece by piece

Six ideas that explain how Tor works, and where its protection ends.

Relays: three volunteers instead of one road

Normally your device connects more or less directly to a website, and every network along the way can see where the traffic comes from and where it goes. Tor sends it through relays instead: computers run by volunteers and organisations around the world. The Tor Project explains that Tor “passes your traffic through at least 3 different servers before sending it on to the destination.”

The three roles have names. The guard relay is “the first relay (hop) in a Tor circuit”; the middle relay “acts as the second hop”; and the exit relay is “the final relay in a Tor circuit, the one that sends traffic out to its destination.” The chain of three is called a circuit.

Why it matters to you: The site you visit sees the exit relay’s IP address, not yours. Your own address, one of the first links explored in this course, stops at the guard.

Layered encryption: why no relay sees the whole picture

Before your traffic leaves your device, Tor wraps it in several layers of encryption, one for each relay. Each relay removes only its own layer. The Tor Project puts it simply: “each relay along the way knows only which relay gave it data and which relay it is giving data to.”

So the guard knows your IP address but not your destination; the exit knows the destination but not who you are; the middle knows neither. The Tor Project’s comparison page says this design “prevents any single relay or provider from knowing both your identity and your online activity.”

Why it matters to you: Anonymity on Tor does not depend on trusting one company. It depends on the relays in your circuit not all being watched or run by the same party, which is why relays are run by many different people and organisations.

Tor Browser: the network plus a careful browser

The Tor Project describes Tor Browser as “a version of Firefox that fixes many privacy issues”. The network hides your address; the browser deals with the other links.

On its home page, the Tor Project says that “Tor Browser isolates each website you visit so third-party trackers and ads can’t follow you”, and that it “aims to make all users look the same”, so that a browser fingerprint is less useful. Installing it and checking that you have the genuine version are covered in the next resource of this section.

Why it matters to you: Sending an ordinary browser through Tor would hide your IP address but leave cookies and fingerprints in place. Tor Browser is built to loosen both kinds of link together.

What the exit relay can see, and why HTTPS still matters

The exit relay is where your traffic leaves the Tor network for the open internet. The Tor Project is frank about it: a dishonest exit “can see the traffic you sent into Tor”, although “It won’t know who sent this traffic.” With encryption such as HTTPS, “it will only know the destination.” The EFF adds that “It’s technically possible that Tor exit nodes may be monitored.”

The Tor Project’s support pages include a visual comparison of what observers can see with and without Tor and HTTPS, and suggest switching on HTTPS-Only Mode in Tor Browser.

Why it matters to you: Tor hides where you connect from; HTTPS protects what you send. A password typed on a page without HTTPS could still be read at the exit, even if nobody knows it is yours.

Who uses Tor, and for which legitimate reasons

The Tor Project’s mission is “To advance human rights and freedoms by creating and deploying free and open source anonymity and privacy technologies”. #! DYNAMIC

Its collection of user stories, written anonymously by people “who rely on Tor to protect their privacy and anonymity”, is grouped under themes such as activism, anti-censorship, freedom of information, press freedom and privacy.

Besides activism and press freedom, many stories are filed under privacy or freedom of information: ordinary reasons to read and search without being followed. The EFF notes that “You can use Tor to circumvent censorship in a number of countries”.

Why it matters to you: Knowing that ordinary users are part of the crowd matters: using Tor is not, in itself, a sign of having something to hide.

What Tor does not do

Tor does not protect what you reveal yourself. The EFF warns that if you log in to a website over Tor, “that website will be able to identify you and may know that you’re using Tor”. Tor does not hide the fact that you are using Tor from your local network, and it is slower: the EFF notes that “certain websites may not work at all.”

Tor and a VPN are sometimes confused. A VPN, as the Online Privacy resource below explains, routes you through one provider who can see your browsing. The Tor Project contrasts that “single point of trust and failure” with Tor’s several relays. Tor reduces linkability; it does not remove every link.

Why it matters to you: Your own choices, such as signing in or typing your name, can rebuild the link Tor was loosening. Rules on using such tools vary by country, so check the situation where you live.

C. A practical example: Sara’s evening session on press freedom

Sara is 28 and teaches at a secondary school. She also runs an evening citizenship course for adults, and she is preparing a session on press freedom. A colleague tells her in the staff room that Tor is “only for the dark web”. Sara wants to explain it to her adult learners accurately, without glamour or fear. The session is a discussion: nobody installs anything in class.

At home, she imagines using Tor Browser for her research. Her first instinct is practical: sign in to her personal email to send herself the useful links. She also assumes that, because Tor is “secure”, HTTPS no longer matters.

What changed when Sara read the Tor Project’s pages

She did the exercise in section D before trying anything:

• She learnt that signing in to her email in Tor Browser would tell her email provider exactly who was reading, and would tie the whole session to her name.
• She understood that the exit relay could read anything sent without HTTPS, so HTTPS still mattered, perhaps more.
• She read the user stories and found everyday reasons alongside those of journalists and people living under censorship: research without being followed, a wish to choose who learns about you.

She decided to keep research and personal accounts in separate sessions, and to note sources on paper rather than emailing them to herself. For her session, she prepared one sentence for the group: “Tor shares out what is known about your connection so that no single stranger holds all of it, and what you say once you arrive is still up to you.”

D. Try it yourself: a guided tour of how Tor works (10 minutes)

Three short steps. You do not need to install anything: the Tor Project’s own pages explain the network, and you only need a browser and a note. The aim is understanding, not a decision to use Tor.

Step 1 — Read the Tor Project’s definition (3 minutes)

• Open the Tor Project’s support page “What is Tor?” (the address is in section E).
• Note, in your own words, what it says Tor prevents: one thing about the people watching your connection, one thing about the sites you visit.
• Note who runs the relays.

Step 2 — Follow a circuit and the exit (4 minutes)

• Open “Types of relays on the Tor network” and write down the three relay roles in the order your traffic passes through them.
• Then open “How is Tor different from other proxies?” and read the two short questions near the end: what the first server can see, and what the third can see.
• Finally, glance at the user stories page and note two or three of the themes the stories are grouped under.

Step 3 — Answer three questions (3 minutes)

Write a one-line answer to each, without looking back:

1. Which relay knows your IP address, and which one knows the site you are visiting?
2. Why does HTTPS still matter when you use Tor?
3. Name one thing Tor cannot protect, because it depends on what you do.

If an answer feels uncertain, go back to that page only. Three clear answers are a better start than a long list of settings.

Already covered in the Online Privacy course

What Does a VPN Hide? Privacy, Trust and Choosing a Provider
It explains what a VPN hides, why it shifts trust to one provider and how to check that provider; this resource adds how Tor spreads that trust across three relays, and why that matters for anonymity.

What Is HTTPS? What the Padlock Tells You, and What It Doesn’t
It explains what the padlock protects and what stays visible on any network; this resource adds why HTTPS still matters at Tor’s exit relay.

E. Videos, articles and further resources

The Tor Project’s own explanations first, then a digital rights guide and European research. All in English.

The Tor Project

The Tor Project — What is Tor?
The official short definition: a network of volunteer relays, what it prevents, and what Tor Browser is.
https://support.torproject.org/about-tor/introduction/what-is-tor/

The Tor Project — How is Tor different from other proxies?
Why several relays with layered encryption differ from a single proxy, and what the first and third relays can see.
https://support.torproject.org/about-tor/introduction/tor-vs-other-proxies/

The Tor Project — Overview (How Tor works)
How a circuit is built one relay at a time, and why each relay knows only its neighbours.
https://support.torproject.org/about-tor/how-tor-works/overview/

The Tor Project — Types of relays on the Tor network
Guard, middle and exit relays, and what the destination site sees.
https://community.torproject.org/relay/types-of-relays/

The Tor Project — HTTPS encryption and Tor
A visual comparison of what observers can see with and without Tor Browser and HTTPS.
https://support.torproject.org/about-tor/security/https-encryption-and-tor/

The Tor Project — User stories
Anonymous accounts from people who use Tor, grouped by theme, from activism and press freedom to privacy.
https://community.torproject.org/outreach/stories/

Digital rights guide and research

Electronic Frontier Foundation — How to: Use Tor
A plain-language guide to what Tor does, its limits (logging in, speed, visible use) and how to start.
https://ssd.eff.org/module/how-to-use-tor

Austrian Science Fund (FWF) — FuOnA: Future of Online Anonymity
A European research project on the building blocks of online anonymity, with Tor as its starting point.
https://www.fwf.ac.at/en/research-radar/10.55776/P30637

Links checked in November 2026. If an address changes, searching for the title on the organisation’s site usually finds it.

F. The Cyber Welfare Framework: Skills, Awareness, Secure Behaviour

This resource sits on the Skills pillar at level FL3 – Autonomous: understanding a tool well enough to judge for yourself when it fits your needs.

Skills

• Explaining what the guard, middle and exit relays each know, and what none of them knows.
• Reading the Tor Project’s own documentation to check a claim about Tor.
• Telling apart what Tor protects (where you connect from) and what HTTPS protects (what you send).

Awareness

• Understanding that Tor spreads trust across several relays rather than placing it in one provider.
• Knowing that Tor is used for ordinary, legitimate reasons, from avoiding tracking to reading past censorship.
• Recognising that signing in or sharing personal details over Tor rebuilds the link it loosens.

Secure Behaviour

• Choosing Tor in proportion to what you need, not as a habit or a badge.
• Keeping personal accounts out of a session you want to keep unlinked.
• Using HTTPS on every site, with or without Tor.

G. Questions to sit with

• Which of your online activities would you prefer not to be linked to your name, and which do you not mind?
• Whom would you rather trust with your connection: one company you chose, or several strangers who each see only part of it?
• How would you explain to a friend, in one sentence, why using Tor is not the same as hiding something?

H. What to do now

The recommendations (R) and security measures (MS) from the Cyber Welfare database that apply most directly here.

1. Protect what you send

• R9 — Browse only over HTTPS: on Tor, HTTPS keeps the exit relay from reading what you send. The Tor Project suggests switching on HTTPS-Only Mode in Tor Browser.
• Keep what you type on a site without HTTPS to a minimum, whatever network or tool you use.

Minimum commitment: this week, check that HTTPS-only mode is on in the browser you use most.

2. Keep the link loose

• MS9 — Use Tor Browser, and OnionShare for anonymous file sharing, when you need a stronger separation between an activity and your identity. The Tor Project describes OnionShare as a tool for “securely and anonymously sending and receiving files using Tor onion services.” Rules on using such tools vary by country.
• Before choosing Tor for an activity, ask which link you would carry in with you, such as an account or your name.

Minimum commitment: write down one activity of yours that would benefit from being unlinked, and one account you would keep out of that session.

In short

• What is Tor? A network of volunteer relays that carries your connection through three hops, so that no single relay knows both who you are and where you are going.
• Tor Browser adds protection against trackers and fingerprinting on top of the network.
• The exit relay can see traffic without HTTPS, and sites still recognise you if you sign in.
• Tor reduces linkability; your own choices decide how much of that protection you keep.

Related resources in this course

• How to Install Tor Browser and Verify It: Windows, Mac, Linux
• How to Use Tor Browser Safely: Habits That Protect You
• Is Tor Browser Really Connected? Check Your Tor Circuit
• What Your IP Address Reveals: Location, Provider and Metadata

Discover more companion resources from the online courses of the Protect Your Digital Privacy programme.