Tor was originally developed by the U.S. Naval Research Laboratory.
The project grew from research into onion routing, a method that sends communications through multiple relays and wraps them in layers of encryption. Each relay normally learns only where traffic came from and where it should go next, limiting the amount of identifying information visible at any one point.
The Naval Research Laboratory researchers associated with the early work included Paul Syverson, Michael G. Reed, and David Goldschlag. The Tor software project was later released under a free and open-source model, and the Tor Project became an independent nonprofit organization in 2006.
Tor is not the same as a conventional VPN. A VPN usually asks users to trust one provider, while Tor distributes knowledge across relays. Tor also does not guarantee anonymity if users reveal identifying information themselves or use insecure applications.