Onion Routing


Ever wanted, or needed, to surf the Web anonymously? Intelligence officers have this need, but so do others. Anonymizing proxies can make it so that the site you visit doesn't know who you are, but they don't protect you from instream eavesdroppers or your own company or ISP. Now there's an open source project you can use to protect your communications called Tor.

The Naval Research Lab came up with a concept called "onion routing" to make it difficult for any one entity to be able to piece together traffic information about Web usage to determine who's using the Web for what. Its not perfectly anonymous, with enough time and some court orders, you could figure it out, but its not easy. The concept is pretty simply. Each message packet in a network transaction is packaged with instructions about the next network hop and then encrypted. This process is repeated, at least three times. As each router gets the message, it unpeels one layer and then uses the enclosed routing instructions to send the message on. As a consequence, any one router has only local routing information.

Tor is the second generation onion router. The Tor client behaves like a SOCKS proxy, so as long as you're client can talk SOCKS, you can use Tor. There are currently about 35 operations Tor nodes. You may want to consider setting one up, but you only need the client to make use of the network.