Tor

Tor, short for "The Onion Router", is a free and open-source software for enabling anonymous communication. It directs Internet traffic through a worldwide overlay network consisting of thousands of relays, concealing a user's location and usage from network surveillance and traffic analysis. Tor is an implementation of onion routing, developed in the mid-1990s by United States Naval Research Laboratory employees.

The Tor network operates on the principle of onion routing, where the user's data is encrypted in layers and passed through several relays. Each relay decrypts a layer of encryption to reveal only the next relay in the circuit until the final relay decrypts the innermost layer and sends the original data to its destination without revealing the source IP address. This process makes it extremely difficult for any single point in the network to link the connection's source and destination.

Tor is used for various purposes, including protecting personal privacy from marketers and identity thieves, circumventing censorship, and allowing journalists, human rights workers, and others to communicate more safely. It also enables access to .onion sites, which are special-use top level domains accessible only through Tor. These hidden services provide a platform for whistleblowers, dissident movements, and others requiring heightened anonymity and security.