If you're concerned about your online privacy and object to having spyware and adware installed on your computer without your permission, then you've probably already installed an anti-spyware program. You now feel that you can rest easy, safe in the knowledge that what you do and where you go on the Internet is your own personal, private business. Wrong.

Photo credit: Lucretius

Any Web-based resource you access can gather personal information about you through your unique IP address - your Internet ID. Once you have accessed a site, it can log your IP address and track your subsequent movements. This totally legal practice is termed 'Traffic Analysis' by the organizations and businesses that profit from it. Do a search on Google and you will find a multitude of legitimate businesses offering software-based services that enable client organizations to undertake Traffic Analysis.

In a more sinister context, however, having knowledge of your IP address can enable a Web site to deny you access to certain online sites and resources. In a worst case scenario, information about your IP address and your operating system can enable hackers to gain access to your hard drive.

Tor is a toolset for organizations and people wanting to improve their safety and security on the Internet by anonymizing their Web browsing and Instant Messaging. Tor also provides a platform on which software developers can build new applications with built-in anonymity, safety, and privacy features.

Like so many advanced technological innovations, Tor is a by-product of some very heavyweight research carried out by the US military establishment, namely the U.S. Naval Research Laboratory's Onion Routing program, with support from the ONR and DARPA.

Tor ensures that your Internet-based communications are "bounced" around a distributed network of servers, called onion routers.

Tor uses a network of 'virtual tunnels' which allows individuals to keep remote websites from tracking them. They can also use it to connect to resources such as news sites or Instant Messaging services that are blocked by their local Internet service providers (ISPs).

The variety of people who use Tor is actually part of what makes it so secure. Tor hides you among the other users on the network, so the more populous and diverse the user base for Tor is, the more your anonymity will be protected.

"Instead of taking a direct route from source to destination, data packets on the Tor network take a random pathway through several servers that cover your tracks so no observer at any single point can tell where the data came from or where it's going. This makes it hard for recipients, observers, and even the onion routers themselves to figure out who and where you are. Tor's technology aims to provide Internet users with protection against "traffic analysis," a form of network surveillance that threatens personal anonymity and privacy, confidential business activities and relationships, and state security."

"Tor aims to make traffic analysis more difficult by preventing eavesdroppers from finding out where your communications are going online, and by letting you decide whether to identify yourself when you communicate. Tor's security is improved as its user base grows and as more people volunteer to run servers. Please consider installing it and then helping out. Part of the goal of the Tor project is to deploy a public testbed for experimenting with design trade-offs, to teach us how best to provide privacy online. We welcome research into the security of Tor and related anonymity systems, and want to hear about any vulnerabilities you find. Tor is an important piece of building more safety, privacy, and anonymity online, but it is not a complete solution. And remember that this is development code—it's not a good idea to rely on the current Tor network if you really need strong anonymity."

Tor is supported by the Electronic Frontier Foundation, a donor-supported membership organization "working to protect our fundamental rights regardless of technology; to educate the press, policymakers and the general public about civil liberties issues related to technology; and to act as a defender of those liberties".