Peer-to-Peer

Chapter 9. Freenet

Adam Langley, Freenet

Freenet is a decentralized system for distributing files that demonstrates a particularly strong form of peer-to-peer. It combines many of the benefits associated with other peer-to-peer models, including robustness, scalability, efficiency, and privacy.

In the case of Freenet, decentralization is pivotal to its goals, which are the following:

• Prevent censorship of documents

• Provide anonymity for users

• Remove any single point of failure or control

• Efficiently store and distribute documents

• Provide plausible deniability for node operators

Freenet grew out of work done by Ian Clarke when he was at the University of Edinburgh, Scotland, but it is now maintained by volunteers on several continents.

Some of the goals of Freenet are very difficult to bring together in one system. For example, efficient distribution of files has generally been done by a centralized system, and doing it with a decentralized system is hard.

However, decentralized networks have many advantages over centralized ones. The Web as it is today has many problems that can be traced to its client/server model. The Slashdot effect, whereby popular data becomes less accessible because of the load of the requests on a central server, is an obvious example.

Centralized client/server systems are also vulnerable to censorship and technical failure because they rely on a small number of very large servers.

Finally, privacy is a casualty of the structure of today’s Web. Servers can tell who ...