Free Net

[100] What is Freenet ?

[110] Freenet as an anonymity service

Freenet is free software which lets you publish and obtain information on the Internet without fear of censorship.
To achieve this freedom, the network is entirely decentralized and publishers and consumers of information are anonymous. Without anonymity there can never be true freedom of speech, and without decentralization the network will be vulnerable to attack.

Communications by Freenet nodes are encrypted and are "routed-through" other nodes to make it extremely difficult to determine who is requesting the information and what its content is.

Users contribute to the network by giving bandwidth and a portion of their hard drive (called the "data store") for storing files. Unlike other peer-to-peer file sharing networks, Freenet does not let the user control what is stored in the data store. Instead, files are kept or deleted depending on how popular they are, with the least popular being discarded to make way for newer or more popular content. Files in the data store are encrypted to reduce the likelihood of prosecution by persons wishing to censor Freenet content.

The network can be used in a number of different ways and isn't restricted to just sharing files like other peer-to-peer networks. It acts more like an Internet within an Internet. For example Freenet can be used for:

Freenet is not just theoretical, it has been downloaded by over 1.2 million users since the project started, and it is used for the distribution of censored information all over the world, including countries such as China and the Middle East. Ideas and concepts pioneered in Freenet have inspired hundreds of academic papers in the fields of computer communication, security, and law. Freenet has also received significant coverage in the mainstream press.

[120] Freenet as a Content Distribution System

In addition to its anonymity features, Freenet is also an effective way to distribute large files - often achieving download speeds faster than other content distribution systems.
As a content distribution network Freenet has the following advantages:

Information can be inserted into Freenet for download without any reliance on a centralized server. All the inserter needs to do is give the content's "key" to someone else and they will be able to download it.

Many CDN architectures only allow peers which have already downloaded a file to share it with other peers. Freenet will adaptively cache information on peers as necessary to meet demand regardless of what that peer has downloaded. This allows Freenet to "scale-up" much more quickly than most solutions for popular files, and improves load-balancing.

Freenet has long-supported the concept of "Content Hash Keys" which guarantee the integrity of retrieved data. This approach has since been adopted by other architectures. Freenet also supports "Signed Subspace Keys" which allow content to be digitally signed. This also allows content integrity to be guaranteed, but is more flexible than CHKs.

In-common with some other CDN architectures, Freenet employs "Forward Error Correction", which allows files to be reconstructed even if some of the parts of that file can't be retrieved. Uniquely, Freenet also supports "healing", which involves the reconstruction and reinsertion of missing file components.