Ever wondered how to remain anonymous or circumvent internet censorship while dealing with sensitive issues online?

Electronic Frontier Foundation, patron of online civil liberties, on Wednesday launched the Tor Challenge, a project aimed at protecting the anonymity of internet users. Tor is a volunteer system that consists of servers spread across the globe, and a downloadable software that enables access to the network.

When you use the Tor software for your online communications and transcations, your IP address remains hidden. Tor relays, also referred to as routes or nodes, are the receivers, carriers and deliverers of data in the network.

Data which travels from the source to the receiver traverse numerous relays scattered across the network without revealing its original source or target, to any individual relay at any point of time. To be precise, no relay will be a pointer to the greater scheme of things, even if it is compromised.

This seemingly simple working model of Tor guarantees what encrypted networks and data can't. The very common form of Internet surveillance known as Traffic Analysis cannot be tackled with encryption since the internet data packets have two parts, of which only the data part remains concealed.

The header part, which contains critical information like source, target, size and timing of the transmission, can be accessed by a third party. It is near impossible to send data without revealing, at least some crucial information about sender to the recipients, intermediaries like Internet Service Providers or unauthorized agents.

Tor disperses the data across the relays in its network which is somewhat akin to the case of an individual trying to lose somebody, who tailgates, by taking multiple lanes to reach the destination. It is difficult even for a sophisticated spy-agent to locate the sender or recipient or content, by accessing a relay because that relay would know only those relays from where it received.

It is practically impossible to hack each and every relay in the network to trace the entire path with just speculations about the kind of data one might be able to access at the end.

This principle points to the most apparent detail: The more relays in Tor network, the more chances of the user staying anonymous. Tor Challenge executed by EFF is good if the user runs a relay to protect the privacy.

Another area where Tor scores is its ability to connect the user anonymously with other services online. It can also protect publishers from the censor, keeping their identity anonymous. Connecting to a whistle-blower, overcoming the censors (remember China's) and voicing sensitive opinions on issues of national interests without getting caught -- are some of the features that Tor offers.

Users need not provide real names and locations to register or sign up for an online service using Tor, says the foundation which launched it. Tor hasn't been into any legal cases yet, but EFF doesn't promise that it will never be.