Tor

The object

Tor, "The Onion Router," had its first public release on 20 September 2002, when Roger Dingledine announced an early version on the or-dev mailing list. Its lineage runs back to the mid-1990s, to onion-routing research by Paul Syverson, Michael Reed, and David Goldschlag at the U.S. Naval Research Laboratory in Washington. Dingledine and Nick Mathewson, both MIT-trained, rebuilt the idea into the second-generation design they described in a 2004 USENIX Security paper, "Tor: The Second-Generation Onion Router." It wraps each request in nested layers of encryption (the onion) and bounces it through a circuit of three volunteer-run relays, so that the entry relay knows who you are but not where you are going, the exit relay knows the destination but not the source, and no single point knows both.

Anonymity needs company

Tor's central insight is social, not just cryptographic: a system that hides one person is useless, because that person stands out. Anonymity loves company: the more varied the traffic sharing the network, the better everyone hides. So Tor was released free and open under a BSD license, and it survives on relays run by volunteers worldwide, numbering in the thousands. That logic produced an unusual alliance: much of the early and ongoing funding has come from the U.S. government (the Naval Research Laboratory, DARPA, and later the State Department and the Broadcasting Board of Governors) because a tool that protects an American official is only credible if it also protects the journalist and the dissident beside them. The nonprofit Tor Project was founded in 2006 to steward the work.

Why it matters

Tor carries PGP's argument forward a decade. PGP hid the contents of a message; Tor hides the fact and pattern of communication itself, the metadata that often matters more than the words. It became essential infrastructure for journalists, dissidents, and ordinary people under surveillance: it helped carry information out during the 2010–2011 Arab Spring, it underpins the SecureDrop systems newsrooms use to receive leaks, and documents disclosed by Edward Snowden in 2013 revealed an NSA presentation, "Tor Stinks," conceding the agency could not reliably de-anonymize all users at will. It is also a permanent point of tension between privacy as a right and the state's desire to see, since the same onion-routed hidden services that shelter the vulnerable can shelter criminal markets. The phreaker's question about who controls a network is still being asked, now in onion layers.

The lesson it set loose

Some freedoms can only be built collectively. You cannot be private alone on a network; privacy at scale is a public good that has to be volunteered into existence. Each relay added makes every other user a little safer, the defining property of a commons. Tor made anonymity an infrastructure project, and it proved that a commons can defend the individual.