The Protocol for Anonymous Communication Over the Internet

Wearing a mask is a bad way to manage anonymity over the long run.

Maintaining anonymity on the Internet can be about more than keeping your privacy. If you are living in an oppressive regime, or contacting someone there, good anonymity means the difference between life and death.

Two protocols were designed with anonymity and untraceability in mind. Tor, or The Onion Router, is a web proxy that encrypts information and renders it untraceable to you. Mixmaster is an anonymizing remailer. It will take mail sent to it, obscure the address, and pass it onto the correct destination.

Tor or The Onion Router

Tor is called The Onion Router because data is sent through a network of routers in special packets that resemble onions--they have many layers. When you send a request for a website through a Tor network, your computer makes a special capsule for the data.

The capsule has an address on top, the first address it goes to. When it gets there, that computer can open the packet and see the next section. The only part of the next section that isn't in code is another address, so it sends the packet to another part of the network. This goes on several times. Each computer in the network only knows how to decrypt the address of the computer in the chain until your packet reaches an "exit node" that opens the last layer and sends the packet on to the website you wanted to go to. Packets from the website go in reverse, with each stop adding a layer of code you can open but no one else can.

Using Tor

Tor is downloadable as a bundle of several pieces of software. It includes the Tor software, Vidalia - a program that makes using the Tor software easier, Torbutton - a Firefox extension that allows you to turn Tor usage on and off quickly, and Polipo, a web proxy. The programs in the bundle are all configured to work together. If you don't already have Mozilla Firefox web browser, you might want to consider downloading it first.

Using Tor is a matter of installing everything and then starting Vidalia to make sure that Tor is working. Once it's set up and running, your IP address will be masked until you shut it off.

Mixmaster, the Anonymous Remailer

Mixmaster covers the other end of anonymity, e-mail. Setting up a Mixmaster node on your broadband connection allows you and others to send and forward email through an anonymizing network. Once your computer has joined the network, any emails sent via Mixmaster will be multiply anonymized through different machines all across the Internet. Your computer will also be used to pass messages within the network, if you allow it. The more machines that a given message passes through before being sent to its final destination, the stronger its anonymity.

Using Mixmaster

Mixmaster is not available pre-compiled for Microsoft Windows. Setting up a Mixmaster node will require you to set up a computer running Linux, Unix, or FreeBSD for their operating system. Setup of the node requires the ability to administrate the server and install multiple programs to it. You will need to install and configure a normal e-mail server and either PGP or GPG. PGP/GPG are two different programs that encrypt and decrypt advanced cryptography. Mail messages sent between nodes that do not get sent onto the e-mail's target are all encrypted using these programs. Mixmaster is a very powerful anonymity tool, but its design unfortunately precludes use by most people.

References

• The Tor Project: How it Works.
• Mixmaster: Official Mixmaster Remailer FAQ
• The Privacy Protection Office: The Anonymity FAQ