# Tor

> A volunteer network that hides who you are by bouncing traffic through three relays.

- Level: Intermediate
- Topics: Networks, Security
- URL: https://tidbit.legios.com.ar/tor/
- In Spanish: [Tor](https://tidbit.legios.com.ar/es/tor/)

**Tor** (originally "The Onion Router") is a free network that makes it hard to tell who is visiting which website. Instead of going straight from your computer to the site, your traffic hops through three relays, servers run by volunteers around the world. Roughly seven thousand relays are online at any time, and the software is maintained by the nonprofit Tor Project. Most people use it through the Tor Browser, a modified Firefox.

The trick is **onion routing**. Before sending, your browser wraps the message in three layers of encryption, one for each relay. The first relay (the guard) removes its layer and only learns that the data came from you and goes to the middle relay. The middle relay only knows the guard and the exit. The exit relay removes the last layer and sends the request to the website, which sees the exit's IP address, not yours. No single relay knows both who you are and what you are visiting.

Journalists, activists in censored countries, abuse survivors and ordinary people who value privacy use Tor; so do criminals, which is why it is often associated with the dark web, where sites with `.onion` addresses are reachable only through Tor. It is slower than a normal connection because of the extra hops. And it has limits: the exit relay can read traffic that is not protected by HTTPS, and logging into your personal accounts, or downloading files and opening them outside the browser, can reveal who you are anyway.

## An analogy

A letter inside three sealed envelopes, each addressed to a different courier. Each courier opens only their envelope and finds the next address. The first knows who sent it but not where it ends up; the last knows where it goes but not who sent it.

## Keep in mind

- Traffic passes through three volunteer relays: guard, middle and exit.
- Layered encryption means no relay knows both the sender and the destination.
- Websites see the exit relay's IP address, not yours.
- Slower than normal browsing, and HTTPS is still needed past the exit relay.

## Go deeper

- [The Tor Project](https://www.torproject.org/)
- [Tor support and FAQ](https://support.torproject.org/)
- [Tor (network) on Wikipedia](https://en.wikipedia.org/wiki/Tor_(network))

## Related terms

- [Website](https://tidbit.legios.com.ar/website/): A set of web pages under one address, stored on a server and opened in a browser.
- [Server](https://tidbit.legios.com.ar/server/): A computer whose job is to answer requests from other computers, all day, every day.
- [Dark web](https://tidbit.legios.com.ar/dark-web/): Websites that are reachable only with special software that hides who is talking to whom.
- [Mozilla](https://tidbit.legios.com.ar/mozilla/): The nonprofit-owned organization behind the Firefox browser and an open web.
- [Web browser](https://tidbit.legios.com.ar/web-browser/): The app that fetches web pages from the internet and draws them on your screen.
- [Encryption](https://tidbit.legios.com.ar/encryption/): Scrambling data so that only someone with the key can read it.
- [IP address](https://tidbit.legios.com.ar/ip-address/): The number that identifies a device on a network, like a postal address.
- [HTTPS](https://tidbit.legios.com.ar/https/): The padlock in your browser: web traffic nobody in between can read.