P2P

Like conventional P2P networks, anonymous P2P networks can implement either opennet or darknet (often named Friend to Friend) network type. This describes how a node on the network selects peer nodes:

* In opennet network, peer nodes are discovered automatically. There is no configuration required but little control available over which nodes become peers.
* In a darknet network, users manually establish connections with nodes run by people they know. Darknet typically needs more effort to set up but a node only has trusted nodes as peers.

Some networks like Freenet support both network types simultaneously (a node can have 5 manually added darknet peer nodes and 5 automatically selected opennet peers) .

In a friend-to-friend (or F2F) network, users only make direct connections with people they know. Many F2F networks support indirect anonymous or pseudonymous communication between users who do not know or trust one another. For example, a node in a friend-to-friend overlay can automatically forward a file (or a request for a file) anonymously between two friends, without telling either of them the other’s name or IP address. These friends can in turn forward the same file (or request) to their own friends, and so on. Users in a friend-to-friend network cannot find out who else is participating beyond their own circle of friends, so F2F networks can grow in size without compromising their users’ anonymity.

Some friend-to-friend networks allow the user to control what kind of files can be exchanged with friends within the node, in order to stop them from exchanging files that user disapproves of.

Advantages and disadvantages of opennet compared to darknet are disputed, see Friend to Friend article for summary.

Originally, anonymous networks were operated by small and friendly communities of developers. As interest in anonymous P2P increased and the user base grew, malicious users inevitably appeared and tried different attacks. This is similar to the Internet, where widespread use has been followed by waves of spam and distributed denial-of-service attacks. Such attacks may require different solutions in anonymous networks. For example, blacklisting of originator network addresses does not work because anonymous networks conceal this information.

There are many reasons to use anonymous P2P technology; most of them are generic to all forms of online anonymity.

P2P users who desire anonymity usually do so as they do not wish to be identified as a publisher (sender), or reader (receiver), of information. Common reasons include:

* The material or its distribution is illegal or incriminating
* Material is legal but socially deplored, embarrassing or problematic in the individual’s social world (for example, anonymity is seen as a key requirement for organizations like Alcoholics Anonymous)
* Fear of retribution (whistleblowers, unofficial leaks, and activists who do not believe in restrictions on information or knowledge)
* Censorship at the local, organizational, or national level
* Personal privacy preferences such as preventing tracking or datamining activities

A particularly open view on legal and illegal content is given in The Philosophy Behind Freenet.

Governments are also interested in anonymous P2P technology. The United States Navy funded the original onion routing research that led to the development of the Tor network, which is now funded by the Electronic Frontier Foundation.

An anonymous P2P computer network is a particular type of peer-to-peer network in which the users are anonymous or pseudonymous by default. The primary difference between regular and anonymous networks is in the routing method of their respective network architectures. These networks allow the unfettered free flow of information, legal or otherwise.Interest in anonymous P2P has increased in recent years for many reasons, including distrust of governments (especially in undemocratic regimes), mass surveillance and data retention, and lawsuits against bloggers.Such networks may also appeal to those wishing to share copyrighted files illegally - organizations such as the Recording Industry Association of America and the British Phonographic Industry have successfully tracked and sued users on non-anonymous P2P networks