Peer to peer networking has become very popular amongst children.

The programs required to join a P2P community can be downloaded off the Internet (usually for free) and easily installed on home computers. Files (such as music, video or pictures) can easily be located, downloaded and then shared out to others. Large quantities of people can become members of P2P communities thus increasing communication opportunities for children. There is often no limit to the amount of downloads that can be performed through the network, or the amount of time spent online in the community. Many P2P communities include other popular Internet services such as chat and instant messaging. There are many P2P communities that children can preview and then become a member of if they wish.

A friend-to-friend (or F2F P2P) computer network is a particular type of anonymous P2P in which people use direct connections with their "friends". F2F software only allows people you trust (using IP addresses or digital signatures you trust) to exchange files directly with your computer. Then your friends' own friends (and so on) can indirectly exchange files with your computer, never using your IP address.

These networks are also called private P2P though they can grow in size without compromising the users anonymity.

Uses of F2F

F2F prevents random people from proving that your IP address can effectively be used to get some controversial files (and as soon as you know all the IP addresses of your friends, you can even use a firewall to block all the other addresses from accessing your F2F port) Since F2F applications use link encryption and don't need end-to-end encryption to achieve their goals, they allow you to control (using your private key) what kind of files a friend exchanges with your node, in order to stop him from exchanging files that you disapprove of. Stop him by removing his public keys or by using a firewall to slow or block his connection to your node.

Far fewer security problems: since only your friends can connect to your node, no random cracker can try to break into your computer by connecting with your P2P node and then using a bug in the communication part of the software. You can exchange crypt keys face to face with your close friends, thus avoiding man in the middle attacks. Dangerous documents (i.e. with viruses, buffer overflow attacks...) could even be avoided using strong reputation based networks (see "Future uses" below). Third party storage (e.g. FTP, Web, email servers) can be used to get faster downloads and to prevent your ISP from logging your friends' IP addresses (using encryption with the third party).

Future uses of F2F

Strong encrypted F2F networks will mainly use strong symmetric encryption (in particular, the only theoretically secure one-time pad) for every link. This can only be achieved in real F2F networks since when you communicate with someone you never met in person, you have to use asymmetric encryption (along with some serious man in the middle problems).

Online reputations could be constructed and verified using a strong encrypted F2F network: each document on this network would be automatically given a new trust rating by each node that forwards it (new_trust = old_trust * local_reputation_of_the_provider). If a document appears to be incorrect then you can manually decrease the local reputation of the friend that sent it to you (the provider) and decrease the trust rating of this document. You can even block this document from being exchanged again through your node.

Such a strong reputation network could be safely used to implement a peer to peer system of electronic money based on the principles of Altruistic Economics; such a system would, according to its advocates, eliminate the inequities inherent in the present system of centralized money.