# Dark web

> Websites that are reachable only with special software that hides who is talking to whom.

- Level: Basic
- Topics: Security, Networks
- URL: https://tidbit.legios.com.ar/dark-web/
- In Spanish: [Dark web](https://tidbit.legios.com.ar/es/dark-web/)

The **dark web** is a small part of the internet made of sites you cannot open with a normal browser or find on a search engine. They live on overlay networks, the best known being **Tor**, and have addresses ending in `.onion`. Visiting them requires software like the Tor Browser, which is designed so that neither the site nor anyone watching the network can easily tell who is visiting.

It helps to separate three layers. The **surface web** is everything a search engine can find. The **deep web** is everything behind a login or not indexed: your email inbox, your bank account, a company's intranet. It is by far the largest part, and it is perfectly ordinary. The dark web is a thin slice on top that is deliberately hidden and anonymous.

The anonymity comes from **onion routing**. Your traffic is wrapped in several layers of encryption and bounced through three volunteer-run relays around the world. Each relay removes one layer and only learns the previous and next stop, so no single point sees both who you are and where you are going. The idea came out of research at the US Naval Research Laboratory in the 1990s, and today the nonprofit Tor Project maintains the software.

People use it for very different things. Journalists receive tips from sources there, people in countries with censorship use it to read the open web, and several major news outlets run `.onion` versions of their sites. It also hosts illegal markets, forums where stolen data is sold, and many scams. Using Tor is legal in most countries, but the usual laws still apply to what you do with it. For most people, the dark web matters mainly as the place where leaked passwords end up, which is why changing them after a breach matters.

## An analogy

Sending a letter inside three sealed envelopes through three couriers. Each courier opens only the outer envelope to see where to take it next, so none of them knows both who sent it and who finally receives it.

## Keep in mind

- Sites reachable only through networks like Tor, with addresses ending in `.onion`.
- Not the same as the deep web, which is just everything behind a login.
- Onion routing passes traffic through three relays, each seeing only part of the path.
- Used both for privacy and free speech and for crime; using Tor itself is legal in most countries.

## Go deeper

- [Dark web on Wikipedia](https://en.wikipedia.org/wiki/Dark_web)
- [History of Tor (The Tor Project)](https://www.torproject.org/about/history/)

## Related terms

- [Internet](https://tidbit.legios.com.ar/internet/): A worldwide network of networks that lets any connected device reach any other.
- [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.