What is the Tor network? The anonymous internet, explained

The Tor network was created in the early 2000s as a project at the Naval Research Laboratory, a research institute of the U.S. Army. Since 2006, the independent non-profit organization The Tor Project has been responsible for the operation and further development of the network. The aim of the organization is to provide a free option for anonymizing connection data on the internet. The Tor Project receives around 85 percent of its funding from several U.S. authorities, with the remaining 15 percent coming from private sponsors and non-governmental organizations.

Tor originally stood for “The Onion Router”: Anyone who dials into the network is routed through three randomly selected Tor servers, which lie one behind the other like the skins of an onion and are known as nodes. The website visited therefore only ever sees the IP address of one Tor server, the so-called exit server. The visitor’s address remains hidden. The individual Tor servers only know the addresses of the upstream and downstream stations via which the data is forwarded. The connection changes every 10 minutes and then runs via other, randomly selected nodes. Only the access node remains the same for around two to three months.

Within the Tor network, the transmitted data is encrypted; it is only decrypted again on the exit server. Tor users should be aware that the data they transmit, such as the information they enter on websites or social media, is stored in plain text behind the exit node. If you want to communicate confidentially with other people via Tor, you should therefore always use encryption. Tor requires a specially configured browser as a client. The Tor browser, which is included in Tails, for example, is based on Mozilla Firefox, which has been customized in its settings for this purpose.

Further reading: How to use the Tor Browser to surf the web anonymously

There are currently around 6,500 Tor servers active worldwide. They are operated by private individuals, companies, and organizations — any user with a DSL connection can set up their own Tor node. However, this openness is also a weak point of Tor: As many connections via Tor are unencrypted due to ignorance, the operators of the Tor servers can read the communication running via their computer if their computer is acting as an exit server. Communication on the Tor network should therefore also be encrypted. If an organization such as a secret service controls large parts of the internet or if it succeeds in infecting a large number of Tor nodes with espionage software, it is also possible to draw conclusions about the network’s users using statistical methods.

Nevertheless, Tor is currently the safest way to move around the internet without being recognized and is used by around two million people every day, many of whom live in surveillance states. The darknet also relies on Tor; its sites and forums can only be accessed via this anonymization network.

Further reading: Meet Darknet, the hidden, anonymous underbelly of the searchable Web