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. 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. ... An IP address (Internet Protocol address) is a unique number, similar in concept to a telephone number, used by machines (usually computers) to refer to each other when sending information through the Internet. ... In cryptography, digital signatures are a method of authenticating digital information often treated, sometimes too closely, as analogous to a physical signature on paper. ...

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

Dan Bricklin introduced the term F2F in August 11, 2000. Daniel S. Bricklin (born 16 July 1951) is the co-creator（with Bob Frankston）of the VisiCalc spreadsheet program. ...

WASTE is an example of a F2F network. MUTE and Napshare are examples of P2P that can be configured to build F2F networks (see External Links below). Waste inside a trash can Waste is unwanted or undesired material left over after the completion of a process. ... Mute comes from mutus, Latin for mum. ... NapShare 0. ...

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 softwares 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 stop his connexion with your node. You can even give his IP to the police, but since he is your friend you may consider to warn him first. Maybe one of his own friends made him do that. Now he can warn this friend in turn. And so on.

• 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 crypto keys from hand to hand 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).

In computing, a firewall is a piece of hardware and/or software which functions in a networked environment to prevent some communications forbidden by the security policy, analogous to the function of firewalls in building construction. ... In computing, a port (derived from seaport) is usually an interface through which data are sent and received. ... Link encryption is an approach to communications security that encrypts and decrypts all traffic at each end a communications line (e. ... A node is a device connected to a computer network. ... PKC, see PKC (disambiguation) Public-key cryptography is a form of modern cryptography which allows users to communicate securely without previously agreeing on a shared secret key. ... Computer security is the effort to create a secure computing platform, designed so that agents (users or programs) can only perform actions that have been allowed. ... Cracker could refer to: Cracker, a type of biscuit Christmas cracker Computer cracker, sometimes incorrectly called a hacker Cracker, a British television series Cracker an American television series also known as Fitz. ... In cryptography, a man in the middle attack (MTM) is an attack in which an attacker is able to read, insert and modify at will, messages between two parties without either party knowing that the link between them has been compromised. ... In computer programming, a buffer overflow is an anomalous condition where a program somehow writes data beyond the allocated end of a buffer in memory. ... A friend-to-friend with third party storage (or F3F for short) computer network is a particular type of F2F in which people store the files they want to exchange in a third party storage (e. ...

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).

• A very strong digital reputation based network could be built using a strong encrypted F2F network: each document on this network would be automatically given a new "trust percentage" 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% 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 exchange electronic money with less greed and corruption: altruists.org[1].

A symmetric-key algorithm is an algorithm for cryptography that uses the same cryptographic key to encrypt and decrypt the message. ... In cryptography, the one-time pad (OTP) is the only theoretically unbreakable method of encryption: the plaintext is combined with a random pad the same length as the plaintext. ... In cryptography, a man in the middle attack (MTM) is an attack in which an attacker is able to read, insert and modify at will, messages between two parties without either party knowing that the link between them has been compromised. ... Similar to the conventional concept of reputation, but achieved while in a pseudonymous state. ... Electronic money (or digital money) refers to cash and associated transactions implemented using electronic means. ...

What F2F is not

• A F2F network is more powerful than an encrypted private FTP server. Your F2F node can forward a file (or a request for a file) anonymously between two of your friends (when forwarding a file or a request between them, your node doesn't tell any of them who is the other and what is the other address). Then these friends' nodes can in turn forward anonymously this same file (or request) to several of their own friends and so on.

• A F2F network is different from a private DirectConnect hub, since inside a DC hub everyone can know and use all the IP addresses of all the users (even when the address is from a friend from a friend from a friend..., someone you may never know).

• GNUnet and Freenet are not F2F because for efficiency reasons (path shortening) they allow some random nodes to connect directly to your node, thus knowing your IP.

This page is about the File Transfer Protocol, a computer protocol. ... Direct Connect is (in its original incarnation) a peer-to-peer file sharing application written by Jon Hess at NeoModus. ... GNUnet is a framework for decentralized, peer-to-peer networking. ... Freenet is a decentralized censorship-resistant peer-to-peer distributed data store. ...

Some security breaches in current networks and their solutions

Besides the fact that current networks don't use provably secure crypto (see "Future uses" above), here are some other breaches:

• In countries where anonymous P2P is forbidden, your ISP can suspect that you use F2F since the networks don't use the default standard ports of popular encrypted programs like webphones or webcams (this solution, along with using a layer of the same encryption as webphones, would be a very simple form of steganography). Using a third party storage (F3F) is a similar solution with more advantages. Networks that use generic VPN software as Metanet does, are less vulnerable to this issue.
• Traffic analysis of all your links by your ISP could easily show that you automatically forward some documents. Solution: add padding bytes to files, and even when you get no more request from a friend, send him some files similar to the ones he usually asks for (this solution is not far from how Napshare and Konspire2b already work now).
• In countries where strong crypto is forbidden (or where you can be forced to give your keys), serious steganography should be used (even for storing files in your hard disk, since it could be seized. See tools like PhoneBookFS[2])

These breaches are not F2F specific: they are shared with most of the current P2P networks. An Internet service provider (ISP) is a business or organization that offers users access to the Internet and related services. ... Steganography is the art and science of writing hidden messages in such a way that no one apart from the intended recipient knows of the existence of the message; this is in contrast to cryptography, where the existence of the message is clear, but the meaning is obscured. ... A friend-to-friend with third party storage (or F3F for short) computer network is a particular type of F2F in which people store the files they want to exchange in a third party storage (e. ... A Virtual Private Network, or VPN, is a private communications network usually used within a company, or by several different companies or organizations, communicating over a public network. ... Traffic analysis is the process of intercepting and examining messages in order to deduce information from patterns in communication. ... In cryptography, padding is the practice of adding material of varying length to the plaintext of messages. ... NapShare 0. ... The title given to this article is incorrect due to technical limitations. ...

External links

• How to configure MUTE or Napshare so you can really specify who are your friends
• Dan Bricklin introduced the term F2F in this article