An anonymous P2P computer network is a particular type of peer-to-peer network in which the users and their nodes are pseudonymous by default. The primary difference between regular and anonymous networks is in the routing method of their respective network architectures. These networks allow for unfettered free flow of information, legal or otherwise.

The P2P community's interest in anonymous P2P has increased rapidly in recent years for many reasons, including distrust of government (especially in undemocratic regimes), and digital imprimatur. Such a network may also appeal to those wishing to share copyrighted music files illegally - the Recording Industry Association of America has successfully tracked and threatened to sue some users on non-anonymous P2P networks.

Anonymous P2P as a misnomer The name anonymous P2P is somewhat of a misnomer. This is because by design, a network node must be pseudonymous since it must have an "address" at which it can be reached by other peer nodes in order to exchange data. However, usually this address, especially on anonymous networks, does not contain any directly identifiable information. Thus a user is highly, but not completely, anonymous. (In friend-to-friend networks, only your friends can know that your address is used to exchange files.)

When receiving data on any network it must come from somewhere and data must have been requested by someone. The anonymity comes from the idea that no one knows who requested the information as it is difficult - if not impossible - to determine if a user requested the data for himself or simply requested the data on behalf of another user. The end result is that everyone on an anonymous network acts as a universal sender and universal receiver to maintain anonymity.

If people are only universal receivers and do not send, then one would know that the information they were requesting was for themselves only, removing any plausible deniability that they were the recipients (and consumers) of the information. Thus, in order to remain anonymous, one must ferry information for others on the network.

Uses of anonymous P2P

There are many personal uses of anonymous P2P technology which include: anonymous web surfing to prevent the tracking of visitors; blocking governments from collecting lists of website visitors; circumvent censorship by employers, ISPs, schools and government; protecting whistle blowers.

Governments are also interested in anonymous P2P technology. The United States Navy is financing the development of Free Haven's Onion Routing Tor network for politically sensitive negotiations and to aid in hiding the identity of government employees for intelligence gathering work.

Anonymous P2P networks are also used for criminal intent, such as the distribution of child pornography, which regularly spawns heated discussions inside the communities, which each find their own answers to that problem (A particularly open view is the Philosophy of Freenet).

Views on the desirability of anonymous P2P

Proponents of anonymous P2P sometimes argue that such technology is desirable and in some cases necessary to ensure freedom of speech and the free flow of information. They claim that true freedom of speech, especially on controversial subjects, is difficult or impossible unless individuals can speak anonymously. They argue that if anonymity were not possible, one could be subjected to threats or reprisals for voicing an unpopular view. This is one reason why voting is done by secret ballot in many democracies.

Opponents argue that while anonymous P2P systems may support the protection of unpopular speech, it also protects illegal activities not protected under free speech, such as fraud, libel, the exchange of illegal pornography, the planning of criminal activities, distribution of untraceable spam, or denial-of-service attacks. They hold that the advantages offered by such systems do not outweigh these disadvantages, and that existing communication channels are already sufficient for unpopular speech.