A F2F network is not just a group of private FTP servers. Alice 's F2F node can automatically forward a file (or a request for a file) anonymously between two friends of Alice. When forwarding a file or a request between two friends, Alice's node doesn't tell 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. {Link without Title}
Unlike other kinds of with "ping packets" disabled, GNUnet with "F2F topology" enabled, and Freenet are examples of software anyone can use to build F2F networks.
Dan Bricklin coined the term "friend-to-friend network" in 2000 . {Link without Title}
- Alice can exchange crypto keys face to face with her close friends, thus avoiding Man In The Middle attacks.
- F2F prevents random people from proving that Alice 's IP address can be used to obtain controversial files. Once Alice knows the IP addresses of all her friends, she can even use a Firewall to prevent any other addresses from accessing her F2F Port .
- Since F2F applications use Link Encryption and don't need end-to-end encryption to achieve their goals, they allow Alice to control what kind of files her friends exchange with her Node . Friends who exchange files that Alice disapproves of can be stopped by removing their Public Keys or by using a firewall to block their connections to her node.
- Far fewer can try to break into her computer by exploiting a bug in the F2F software. Dangerous files (e.g. documents infected with Malware ) could even be avoided using strong reputation based networks (see "future uses" below).
- Fewer Leecher s (or freeloaders). Since a user must use the bandwidth of his own friends, he must act responsibly.
- A private Direct Connect hub is not a F2F network, since any user of a hub can discover the IP addresses of all the other users, even those who are not their friends.
- F2F does not apply to Freenet version 0.5 because for so-called "efficiency reasons" (path shortening) the software automatically makes new connections between nodes. However from version 0.7, Freenet is based on what its authors call a Darknet , which is more precisely a F2F network. Additionally, Freenet 0.7 is "significantly faster" than Freenet 0.5. {Link without Title} .
- Similarly, pseudonymous P2P networks like CSpace or Retroshare Instant Messenger are not F2F since when two computers exchange files, they will get to know each other's IP addresses (there is no anonymous forwarding).
- F2F is not a F2F '''network''' by itself; such software can be used to participate in an existing F2F network, or to launch a new F2F network. Existing networks may be connected to form a larger F2F network. Since new members have to gain the trust of an existing member in order to join a network, it is impossible to know how many separate F2F networks exist. This is why F2F networks are part of the larger family of networks called darknets.
- Online Reputation s could be constructed and verified using a F2F network: each document on the network would be automatically given a new trust rating by each node forwarding it, for example by multiplying the old trust rating by the reputation of the provider. If a document appeared to be incorrect, the recipient could manually decrease the local reputation of the friend who provided it, decrease the trust rating of the document, or even block the document from being exchanged again through her node. (This kind of functionality is already implemented in the Bouillon P2P social wiki.)
- 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.
- F2F networks could avoid the Key Exchange problems of many other networks, such as Man In The Middle attacks, by exchanging encryption keys face-to-face. Users could even exchange One-time Pad s, such as hard disks filled with random bytes, to achieve provably unbreakable encryption.
- Third party storage (e.g. FTP, Web, email servers) could be used to get faster downloads and to prevent Alice's ISP from logging her friends' IP addresses (using encryption with the third party).
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, Alice's software, as AnoNet does, may be less vulnerable to this issue.
- Traffic Analysis of Alice's links by her ISP could easily show that she is automatically forwarding files. One possible solution, implemented in WASTE , is to send and receive a constant stream of meaningless data, so that traffic analysis cannot detect whether meaningful data is being transmitted at any given time. Another possibility would be to add Padding to files.
- In countries where strong crypto is forbidden (or where users can be forced to surrender their keys), Steganography could be used for every connection (and for storing files on a hard disk, since it could be seized). Because steganography involves a secret convention that must be established Out-of-band , only F2F networks could be safe in such countries.
These breaches are not F2F specific: they are shared with most of the current P2P networks.
- B.C. Popescu, B. Crispo, and A.S. Tanenbaum . "Safe and Private Data Sharing with Turtle: Friends Team-Up and Beat the System." 12th International Workshop on Security Protocols, Cambridge, UK, April 2004.
- T. Chothia and K. Chatzikokolakis. "A Survey of Anonymous Peer-to-Peer File-Sharing". In Proceedings of the IFIP International Symposium on Network-Centric Ubiquitous Systems (NCUS 2005), Nagasaki, Japan, volume 3823 of Lecture Notes in Computer Science, pages 744-755. Springer, 2005.
- J. Li and F. Dabek. F2F: Reliable Storage in Open Networks . In 5th International Workshop on Peer-to-Peer Systems (IPTPS '06), Santa Barbara, CA, USA, February 2006.
- Discussion about F2F involving Ian Clarke of Freenet : http://zgp.org/pipermail/p2p-hackers/2005-December/003272.html
- Dan Bricklin coined the term F2F in this article
- F2F page at altruists.org: http://www.altruists.org/projects/ge/ff/
- Adding simple and effective trust measurements to F2F P2P networks is a paper about using a Time-based Currency for trust in F2F.
- Ripple: P2P money for trusted social networks: http://www.masternewmedia.org/news/2005/06/27/p2p_can_cut_banks_out.htm
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