Citizendia

The BitTorrent logo

BitTorrent is a peer-to-peer file sharing (P2P) communications protocol. See Shared resource for the conventional meaning of file sharing File sharing refers to the providing and receiving of digital files over a In the field of Telecommunications, a communications protocol is the set of standard rules for data representation signaling authentication and error detection required to BitTorrent is a method of distributing large amounts of data widely without the original distributor incurring the entire costs of hardware, hosting, and bandwidth resources. Debt AIDS Trade in Africa (or DATA) is a Multinational non-government organization founded in January 2002 in London by U2 's Hardware is a general term that refers to the physical artifacts of a Technology. An Internet hosting service is a service that runs Internet servers allowing organizations and individuals to serve content to the Internet or in newbie terms a way for you Instead, when data is distributed using the BitTorrent protocol, each recipient supplies pieces of the data to newer recipients, reducing the cost and burden on any given individual source, providing redundancy against system problems, and reducing dependence on the original distributor.

The protocol is the brainchild of programmer Bram Cohen, who designed it in April 2001 and released a first implementation on 2 July 2001. Bram Cohen (born 1975 is an American Computer programmer, best known as the author of the Peer-to-peer (P2P BitTorrent protocol, as well as Events 310 - Pope Miltiades is elected 626 - In fear of assassination Li Shimin ambushes and kills his rival Year 2001 ( MMI) was a Common year starting on Monday according to the Gregorian calendar. [1] It is now maintained by Cohen's company BitTorrent, Inc.

Usage of the protocol accounts for significant traffic on the Internet, but the precise amount has proven difficult to measure. BitTorrent Inc, headquartered in San Francisco, California, is an American Corporation that develops peer-assisted Internet content delivery

There are numerous compatible BitTorrent clients, written in a variety of programming languages, and running on a variety of computing platforms. A BitTorrent client is a program that manages torrent downloads A programming language is an Artificial language that can be used to write programs which control the behavior of a machine particularly a Computer. In Computing, a platform describes some sort of Hardware architecture or Software framework (including Application frameworks, that allows

Contents

Operation

In this animation, the coloured bars beneath all of the clients represent individual pieces of the file. After the initial pieces transfer from the seed, the pieces are individually transferred from client to client. The original seeder only needs to send out one copy of the file for all the clients to receive a copy.
In this animation, the coloured bars beneath all of the clients represent individual pieces of the file. After the initial pieces transfer from the seed, the pieces are individually transferred from client to client. The original seeder only needs to send out one copy of the file for all the clients to receive a copy.

A BitTorrent client is any program that implements the BitTorrent protocol. Each client is capable of preparing, requesting, and transmitting any type of computer file over a network, using the protocol. A computer file is a block of Arbitrary Information, or resource for storing information which is available to a Computer program and is usually A peer is any computer running an instance of a client.

To share a file or group of files, a peer first creates a small file called a "torrent" (e. g. MyFile. torrent). This file contains metadata about the files to be shared and about the tracker, the computer that coordinates the file distribution. Metadata ( meta data, or sometimes metainformation) is "data about data" of any sort in any media A BitTorrent tracker is a server which assists in the communication between peers using the BitTorrent protocol. Peers that want to download the file first obtain a torrent file for it, and connect to the specified tracker, which tells them from which other peers to download the pieces of the file.

Though both ultimately transfer files over a network, a BitTorrent download differs from a classic full-file HTTP request in several fundamental ways:

Taken together, these differences allow BitTorrent to achieve much lower cost, much higher redundancy, and much greater resistance to abuse or to "flash crowds" than a regular HTTP server. The Slashdot effect, also known as slashdotting, is the phenomenon of a popular Website linking to a smaller site causing the smaller site to slow down or even temporarily Hypertext Transfer Protocol ( HTTP) is a Communications protocol for the transfer of information on the Internet. However, this protection comes at a cost: downloads can take time to rise to full speed because it may take time for enough peer connections to be established, and it takes time for a node to receive sufficient data to become an effective uploader. As such, a typical BitTorrent download will gradually rise to very high speeds, and then slowly fall back down toward the end of the download. This contrasts with an HTTP server that, while more vulnerable to overload and abuse, rises to full speed very quickly and maintains this speed throughout.

In general, BitTorrent's non-contiguous download methods have prevented it from supporting "progressive downloads" or "streaming playback". But comments made by Bram Cohen in January 2007 suggest that streaming torrent downloads will soon be commonplace and ad supported streaming appears to be the result of those comments.

Creating and publishing torrents

The peer distributing a data file treats the file as a number of identically-sized pieces, typically between 64 kB and 4 MB each. The peer creates a checksum for each piece, using the SHA1 hashing algorithm, and records it in the torrent file. A checksum is a form of Redundancy check, a simple way to protect the integrity of data by detecting errors in data that are sent through space ( Telecommunications Pieces with sizes greater than 512 kB will reduce the size of a torrent file for a very large payload, but is claimed to reduce the efficiency of the protocol [1]. When another peer later receives a particular piece, the checksum of the piece is compared to the recorded checksum to test that the piece is error-free. [3] Peers that provide a complete file are called seeders, and the peer providing the initial copy is called the initial seeder.

The exact information contained in the torrent file depends on the version of the BitTorrent protocol. By convention, the name of a torrent file has the suffix . torrent. Torrent files have an "announce" section, which specifies the URL of the tracker, and an "info" section, containing (suggested) names for the files, their lengths, the piece length used, and a SHA-1 hash code for each piece, all of which is used by clients to verify the integrity of the data they receive. Uniform Resource Locator is an URI which also specifies where the identified resource is available and the protocol for retrieving it A hash function is any well-defined procedure or mathematical function for turning some kind of Data into a relatively small integer, that may

Completed torrent files are typically published on websites or elsewhere, and registered with a tracker. The tracker maintains lists of the clients currently participating in the torrent. [3] Alternatively, in a trackerless system (decentralized tracking) every peer acts as a tracker. This is implemented by the BitTorrent, µTorrent, BitComet, KTorrent and Deluge clients through the distributed hash table (DHT) method. BitTorrent is a Peer-to-peer program developed by Bram Cohen and BitTorrent Inc BitComet (originally named SimpleBT client from versions 011 to 0 KTorrent is a BitTorrent client written in C++ for KDE using the Qt user interface toolkit Deluge is a BitTorrent client, created using Python and GTK+ (through PyGTK) Distributed hash tables ( DHTs) are a class of decentralized distributed systems that provide a lookup service similar to a Hash table: ( name, Azureus also supports a trackerless method that is incompatible (as of April 2007) with the DHT offered by all other supporting clients.

In November 2006, BitTorrent Inc. introduced its "Publish Torrent" service, which creates and hosts a torrent file (seeded from an existing web-hosted media file) and tracks the downloads. The service (http://www.bittorrent.com/publish) requires a client that supports web-seeding (currently the official client, Azureus, µTorrent and anything based on Libtorrent). libtorrent is an Open source implementation of the BitTorrent protocol

Downloading torrents and sharing files

Users browse the web to find a torrent of interest, download it, and open it with a BitTorrent client. The client connects to the tracker(s) specified in the torrent file, from which it receives a list of peers currently transferring pieces of the file(s) specified in the torrent. The client connects to those peers to obtain the various pieces. Such a group of peers connected to each other to share a torrent is called a swarm. If the swarm contains only the initial seeder, the client connects directly to it and begins to request pieces. As peers enter the swarm, they begin to trade pieces with one another, instead of downloading directly from the seeder.

Clients incorporate mechanisms to optimize their download and upload rates; for example they download pieces in a random order to increase the opportunity to exchange data, which is only possible if two peers have different pieces of the file.

The effectiveness of this data exchange depends largely on the policies that clients use to determine to whom to send data. Clients may prefer to send data to peers that send data back to them (a tit for tat scheme), which encourages fair trading. Tit for tat is a highly effective strategy in Game theory for the Iterated prisoner's dilemma. But strict policies often result in suboptimal situations; e. g. , when newly joined peers are unable to receive any data because they don't have any pieces yet to trade themselves or when two peers with a good connection between them do not exchange data simply because neither of them wants to take the initiative. To counter these effects, the official BitTorrent client program uses a mechanism called “optimistic unchoking,” where the client reserves a portion of its available bandwidth for sending pieces to random peers (not necessarily known-good partners, so called preferred peers), in hopes of discovering even better partners and to ensure that newcomers get a chance to join the swarm. [4]

Adoption

A growing number of individuals and organizations are using BitTorrent to distribute their own or licensed material. Independent adopters report[5] that without using BitTorrent technology, and its dramatically reduced demands on networking hardware and bandwidth, they could not afford to distribute their files.

Film, video and music

Broadcasters

Personal material

Software

Games

Network impact

CableLabs, the research organization of the North American cable industry, estimates that BitTorrent represents 18% of all broadband traffic. Metal Gear Online, abbreviated MGO, is a PlayStation 3 exclusive online multiplayer spin-off of the ''Metal Gear series America's Army (also known as AA or Army Game Project) is a Video game owned by the United States Government Cable Television Laboratories, also called CableLabs, is a non-profit Research and development consortium whose members are exclusively Cable television [10] In 2004, CacheLogic put that number at roughly 35% of all traffic on the Internet. [11] The discrepancies in these numbers are caused by differences in the methodology used to measure P2P traffic on the Internet. [12]

Routers that use NAT, Network Address Translation, must maintain tables of source and destination IP addresses and ports. In Computer networking network address translation (NAT is the process of modifying Network address information in datagram packet headers while in transit across Typical home routers are limited to about 2000 table entries while some more expensive routers have larger table capacities. BitTorrent frequently contacts 300-500 servers per second rapidly filling the NAT tables. This is a common cause of home routers locking up. [13]

Indexing

The BitTorrent protocol provides no way to index torrent files. As a result, a comparatively small number of websites have hosted the large majority of torrents linking to (possibly) copyrighted material, rendering those sites especially vulnerable to lawsuits. Several types of websites support the discovery and distribution of data on the BitTorrent network.

Public tracker sites such as The Pirate Bay allow users to search in and download from their collection of . The Pirate Bay is a Swedish Website that indexes and tracks BitTorrent ("torrent" files torrent files; they also run BitTorrent trackers for those files. A BitTorrent tracker is a server which assists in the communication between peers using the BitTorrent protocol. Users can typically also upload . torrent files for content they wish to distribute.

Private tracker sites such as Demonoid operate like public ones except that they restrict access to registered users and keep track of the amount of data each user uploads and downloads, in an attempt to reduce leeching. Demonoid is a Website and BitTorrent tracker that was originated by an anonymous Serbian known only by the Pseudonym Deimos In Computing and specifically on the Internet, being a leech or leecher refers to the practice of benefiting usually deliberately from others' information

There are specialized tracker sites such as FlixFlux for films, bitme for educational content, fullcaliber. FlixFlux is a specialist torrent search site for films The site was originally launched in mid 2006 with a basic search facility and a list of new film releases be for metal music, PureTnA for pornographic content, and tv torrents for television series. Often these will also be private.

Search engines allow the discovery of . torrent files that are hosted and tracked on other sites; examples include Mininova, Monova, Btjunkie, Torrentz and isoHunt. Mininova is one of the largest torrent listing sites The site started in January 2005 as a successor to the (at that time very popular Suprnova BTJunkie is an advanced BitTorrent Search engine. It uses a Web crawler (similar to Google) to search for torrent files from other torrent sites isoHunt is a BitTorrent index with over 1 million torrents in its database and 16 million These sites allow the user to ask for content meeting specific criteria (such as containing a given word or phrase) and retrieve a list of links to . torrent files matching those criteria. This list is often sorted with respect to relevance or number of seeders. Bram Cohen launched a BitTorrent search engine on http://search.bittorrent.com that commingles licensed content with search results. [14] Metasearch engines allow to search several BitTorrent indices and search engines at once. A meta-search engine is a Search engine that sends user requests to several other search engines and/or databases and aggregates the results into a single list or displays them

Legal issues

Main article: Legal issues with BitTorrent

There has been much controversy over the use of BitTorrent trackers. The BitTorrent protocol's wide use for Copyright infringement has led to legal issues with BitTorrent. BitTorrent metafiles themselves do not store copyrighted data, hence BitTorrent itself is not illegal - it is the use of it to copy copyrighted material that contravenes laws in some locations.

Various jurisdictions have pursued legal action against websites that host BitTorrent trackers. High-profile examples include the closing of Suprnova.org, torrentspy. Suprnovaorg is a Swedish (formerly Slovenian based website which distributed torrents for various music org, LokiTorrent, Demonoid (now back online), OiNK.cd and EliteTorrents. LokiTorrent was a BitTorrent indexing service operated by Edward Webber ( "Lowkee") from 2004 until 2005. Demonoid is a Website and BitTorrent tracker that was originated by an anonymous Serbian known only by the Pseudonym Deimos Oink's Pink Palace (frequently written as OiNK) was a prominent BitTorrent tracker located at Oink org. The Pirate Bay torrent website, formed by a Swedish anti-copyright group, is notorious for the "legal" section of its website in which letters and replies on the subject of alleged copyright infringements are publicly displayed. The Pirate Bay is a Swedish Website that indexes and tracks BitTorrent ("torrent" files On May 31, 2006, The Pirate Bay's servers in Sweden were raided by Swedish police on allegations by the MPAA of copyright infringement;[15] however, the tracker was up and running again three days later. Events 1279 BC - Rameses II (The Great (19th dynasty becomes pharaoh of Ancient Egypt. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar.

HBO, in an effort to combat the distribution of its programming on BitTorrent networks, has sent cease and desist letters to the Internet Service Providers of BitTorrent users. A cease and desist (also called C & D) is an order or request to halt an activity or else face legal action An Internet service provider ( ISP, also called Internet access provider or IAP) is a company which primarily offers their customers access to the Internet Many users have reported receiving letters from their ISPs that threatened to cut off their internet service if the alleged infringement continues. [16] HBO, unlike the RIAA, has not been reported to have filed suit against anyone for sharing files as of April 2007. In 2005 HBO began "poisoning" torrents of its show Rome, by providing bad chunks of data to clients. Rome is a BAFTA, Golden Globe and Emmy -nominated historical drama Television series co-created by John Milius [17]

On November 23, 2005, the movie industry and BitTorrent Inc. CEO Bram Cohen, signed a deal they hoped would reduce the number of unlicensed copies available through bittorrent. Events 800 - Charlemagne arrives at Rome to investigate the alleged crimes of Year 2005 ( MMV) was a Common year starting on Saturday (link displays full calendar of the Gregorian calendar. BitTorrent Inc, headquartered in San Francisco, California, is an American Corporation that develops peer-assisted Internet content delivery Bram Cohen (born 1975 is an American Computer programmer, best known as the author of the Peer-to-peer (P2P BitTorrent protocol, as well as com's search engine, run by BitTorrent, Inc. It meant BitTorrent.com had to remove any links to unlicensed copies of films made by seven of Hollywood's major movie studios. BitTorrent Inc, headquartered in San Francisco, California, is an American Corporation that develops peer-assisted Internet content delivery

There are two major differences between BitTorrent and many other peer-to-peer file-trading systems, which advocates suggest make it less useful to those sharing copyrighted material without authorization. First, BitTorrent itself does not offer a search facility to find files by name. A user must find the initial torrent file by other means, such as a web search. Second, BitTorrent makes no attempt to conceal the host ultimately responsible for facilitating the sharing: a person who wishes to make a file available must run a tracker on a specific host or hosts and distribute the tracker address(es) in the . torrent file. Because it is possible to operate a tracker on a server that is located in a jurisdiction where the copyright holder cannot take legal action, the protocol does offer some vulnerability that other protocols lack. It is far easier to request that the server's ISP shut down the site than it is to find and identify every user sharing a file on a peer-to-peer network. An Internet service provider ( ISP, also called Internet access provider or IAP) is a company which primarily offers their customers access to the Internet However, with the use of a distributed hash table (DHT), trackers are no longer required, though often used for client software that does not support DHT to connect to the stream. Distributed hash tables ( DHTs) are a class of decentralized distributed systems that provide a lookup service similar to a Hash table: ( name,

Limitations and security vulnerabilities

Anonymity (or Lack Thereof)

BitTorrent does not offer its users anonymity. It is possible to obtain the IP addresses of all current, and possibly previous, participants in a swarm from the tracker. An Internet Protocol ( IP) address is a numerical identification ( Logical address) that is assigned to devices participating in a Computer network This may expose users with insecure systems to attacks. [4]

Dialup versus Broadband

BitTorrent is best suited to continuously connected broadband environments, since dial-up users find it less efficient due to frequent disconnects and slow download rates. Broadband Internet access, often shortened to just Broadband, is high-speed Internet access—typically contrasted with dial-up access over a Modem

The Leech Problem

Another drawback is that BitTorrent file sharers, compared to users of client/server technology, often have little incentive to become seeders after they finish downloading. The result of this is that torrent swarms gradually die out, meaning a lower possibility of obtaining older torrents. Some BitTorrent websites have attempted to address this by recording each user's download and upload ratio for all or just the user to see, as well as the provision of access to newer torrent files to people with better ratios. Also, users who have low upload ratios may see slower download speeds until they upload more. This prevents (statistical) leeching, since after a while they become unable to download much faster than 1-10 kB/s on a high-speed connection. Some trackers exempt dial-up users from this policy, because they cannot upload faster than 1-3 kB/s. Dial-up Internet Access is a form of Internet access via Telephone lines The user's computer or Router uses an attached Modem connected to a

The Leech Compensation Problem

Some seeders deliberately withhold one specific piece of the data. This results in clients downloading all but the final piece from the seed and from each other, thus leaving a large number of potential seeders once they receive the withheld piece of data.

The reason this is done is to combat the leeching problem described above. With clients each awaiting that one final piece, the seeder ensures that there will be many more seeds once the final piece is released.

The Cheater Problem

There are "cheating" clients like BitThief which claim to be able to download without uploading, and because of this can sometimes download faster than regular clients. BitThief is a Java -based BitTorrent client designed to download from but not upload to BitTorrent networks Such exploitation negatively affects the cooperative nature of the BitTorrent protocol.

Technologies built on BitTorrent

The BitTorrent protocol is still under development and therefore may still acquire new features and other enhancements such as improved efficiency.

Distributed trackers

In June 2005, BitTorrent, Inc. released version 4. BitTorrent Inc, headquartered in San Francisco, California, is an American Corporation that develops peer-assisted Internet content delivery 2. 0 of the Mainline BitTorrent client. This release supported "trackerless" torrents, featuring a DHT implementation which allowed the client to use torrents that do not have a working BitTorrent tracker. Distributed hash tables ( DHTs) are a class of decentralized distributed systems that provide a lookup service similar to a Hash table: ( name, A BitTorrent tracker is a server which assists in the communication between peers using the BitTorrent protocol. Current versions of the official BitTorrent client, µTorrent, BitComet, and BitSpirit all share a compatible DHT implementation that is based on Kademlia. A BitTorrent client is a program that manages torrent downloads BitComet (originally named SimpleBT client from versions 011 to 0 Kademlia is a Distributed hash table for decentralized Peer to peer Computer networks designed by Petar Maymounkov and David Mazières [18] Azureus uses its own incompatible DHT system called the "distributed database", but a plugin is available which allows use of the mainline DHT.

Another idea that has surfaced recently in Azureus is that of virtual torrents. This idea is based on the distributed tracker approach and is used to describe some web resource. Currently, it is used for instant messaging. It is implemented using a special messaging protocol and requires an appropriate plugin. Anatomic P2P is another approach, which uses a decentralized network of nodes that route traffic to dynamic trackers. Anatomic P2P is a decentralised Peer-to-peer network based on the BitTorrent protocol

Most BitTorrent clients also use Peer exchange (PEX) to gather peers in addition to trackers and DHT. Peer exchange ( PEX) is a feature of the BitTorrent Peer-to-peer protocol which like trackers and DHT, can be utilized to gather peers A BitTorrent tracker is a server which assists in the communication between peers using the BitTorrent protocol. Distributed hash tables ( DHTs) are a class of decentralized distributed systems that provide a lookup service similar to a Hash table: ( name, Peer exchange checks with known peers to see if they know of any other peers. With the 3. 0. 5. 0 release of Azureus, all major BitTorrent clients now have compatible peer exchange.

Content delivery

Web seeding was implemented in 2006. The advantage of this feature is that a site may distribute a torrent for a particular file or batch of files and make those files available for download from that same web server; this can simplify seeding and load balancing greatly once support for this feature is implemented in the various BitTorrent clients. In Computer networking, load balancing is a technique to spread work between two or more computers network links CPUs hard drives or other resources in order to get optimal In theory, this would make using BitTorrent almost as easy for a web publisher as simply creating a direct download while allowing some of the upload bandwidth demands to be placed upon the downloaders (who normally use only a very small portion of their upload bandwidth capacity). This feature was created by John "TheSHAD0W" Hoffman, who created BitTornado. BitTornado is a BitTorrent client. It is developed by John Hoffman who also created its predecessor Shadow's Experimental Client. [19]. From version 5. 0 onward the Mainline BitTorrent client also supports web seeds and the BitTorrent web site has a simple publishing tool that creates web seeded torrents. µTorrent added support for web seeds in version 1. 7. The latest version of the popular download manager GetRight supports downloading a file from both HTTP/FTP protocols and using BitTorrent. GetRight is Download manager developed by Headlight Software.

Broadcatching combines RSS with the BitTorrent protocol to create a content delivery system, further simplifying and automating content distribution. Broadcatching is the downloading of digital content that has been made available over the Internet using RSS syndication RSS is a family of Web feed formats used to publish frequently updated works – such as Blog entries news headlines audio and video – in a standardized Steve Gillmor explained the concept in a column for Ziff-Davis in December, 2003. Ziff Davis Inc (ZD is an American publisher and Internet company [20] The discussion spread quickly among bloggers (Techdirt, Ernest Miller, Chris Pirillo, etc. Christopher "Chris" Joseph Pirillo (born) is the founder and maintainer of Lockergnome ). In an article entitled Broadcatching with BitTorrent, Scott Raymond explained:

I want RSS feeds of BitTorrent files. A script would periodically check the feed for new items, and use them to start the download. Then, I could find a trusted publisher of an Alias RSS feed, and 'subscribe' to all new episodes of the show, which would then start downloading automatically — like the 'season pass' feature of the TiVo. Alias is an American " Spy-fi " television series created by J TiVo (pronounced ˈtiːvoʊ is a brand of Digital video recorder (DVR in the United States, Canada, and Australia created by TiVo

—[21]

The RSS feed will track the content, while BitTorrent ensures content integrity with cryptographic hashing of all data, so subscribers to a feed receive uncorrupted content. Cryptography (or cryptology; from Greek grc κρυπτός kryptos, "hidden secret" and grc γράφω gráphō, "I write" A hash function is any well-defined procedure or mathematical function for turning some kind of Data into a relatively small integer, that may

One of the first software clients (free and open source) for broadcatching is Miro. Free software or software libre is Software that can be used studied and modified without restriction and which can be copied and redistributed in modified or unmodified Open source software (OSS began as a marketing campaign for Free software. Miro (previously known as Democracy Player and DTV) is an Internet television application developed by the Participatory Culture Foundation. Other free software clients such as PenguinTV and KatchTV are also now supporting broadcatching. KatchTV is an Internet TV application for the KDE desktop which is popular on Unix-like Operating systems such as Linux.

The BitTorrent web-service MoveDigital has the ability to make torrents available to any web application capable of parsing XML through its standard Representational State Transfer (REST) based interface. Don't change "Extensible" [22] Additionally, Torrenthut is developing a similar torrent API that will provide the same features, as well as further intuition to help bring the torrent community to Web 2.0 standards. Web 20 is a term describing changing trends in the use of World Wide Web technology and Web design that aims to enhance Creativity, secure Alongside this release is a first PHP application built using the API called PEP, which will parse any Really Simple Syndication (RSS 2. PHP is a computer Scripting language. Originally designed for producing Dynamic web pages it has evolved to include a Command line interface capability RSS is a family of Web feed formats used to publish frequently updated works – such as Blog entries news headlines audio and video – in a standardized 0) feed and automatically create and seed a torrent for each enclosure found in that feed. [23]

Encryption

Main article: BitTorrent protocol encryption

Some ISPs throttle (reduce) BitTorrent traffic of their customers because it makes up a large proportion of total traffic and the ISPs don't want to spend money purchasing extra capacity. Protocol encryption ( PE) Message stream encryption ( MSE) or Protocol header encrypt ( PHE) are related features of some Peer-to-peer An Internet service provider ( ISP, also called Internet access provider or IAP) is a company which primarily offers their customers access to the Internet [24]

Protocol header encrypt (PHE) and Message stream encryption/Protocol encryption (MSE/PE) are features of some BitTorrent clients that attempt to make BitTorrent hard to detect and throttle. Protocol encryption ( PE) Message stream encryption ( MSE) or Protocol header encrypt ( PHE) are related features of some Peer-to-peer At the moment Azureus, Bitcomet, KTorrent, Transmission, Deluge, µTorrent,MooPolice, Halite, rtorrent and the latest official BitTorrent client (v6) support MSE/PE encryption. BitComet (originally named SimpleBT client from versions 011 to 0 KTorrent is a BitTorrent client written in C++ for KDE using the Qt user interface toolkit Transmission is a free lightweight BitTorrent client which features a simple interface on top of a Cross-platform back-end Deluge is a BitTorrent client, created using Python and GTK+ (through PyGTK) Halite is the Mineral form of Sodium chloride, Na[[chlorine Cl]] commonly known as rock salt. rTorrent is a Text-based Ncurses BitTorrent client written in C++, based on the libTorrent libraries for UNIX (which

In September 2006 it was reported that some software could detect and throttle BitTorrent traffic masquerading as HTTP traffic. Hypertext Transfer Protocol ( HTTP) is a Communications protocol for the transfer of information on the Internet.

Reports in August 2007 indicated that Comcast was preventing BitTorrent seeding by monitoring and interfering with the communication between peers. Comcast Corporation ( is the largest Cable television company the second largest Internet service provider and (according to the company the fourth largest telephone Protection against these efforts is provided by proxying the client-tracker traffic through the Tor anonymity network or, via an encrypted tunnel to a point outside of the Comcast network. In Computer networks a proxy server is a server (a computer system or an application program which services the requests of its clients by forwarding Tor ( The Onion Router) is a Free software implementation of second-generation Onion routing – a system enabling its users to communicate anonymously The term tunneling protocol is used to describe when one Network protocol called the payload protocol is encapsulated within a different delivery protocol [25] Comcast has more recently called a 'truce' with BitTorrent, Inc. with the intention of shaping traffic in a protocol-agnostic manner. BitTorrent Inc, headquartered in San Francisco, California, is an American Corporation that develops peer-assisted Internet content delivery [26] Questions about the ethics and legality of Comcast's behavior have led to renewed debate about Net neutrality in the United States[27], with Barack Obama stating that he would try to make Comcast's filtering of BitTorrent illegal. See also Network neutrality in the United States See also Network neutrality in Canada Definitions of network neutrality Advocates offer three [28]

In general, although encryption can make it difficult to determine what is being shared, BitTorrent is vulnerable to traffic analysis. Traffic analysis is the process of intercepting and examining messages in order to deduce information from patterns in Communication. Thus even with MSE/PE, it may be possible for an ISP to recognize BitTorrent and also to determine that a system is no longer downloading, only uploading, information and terminate its connection by injecting TCP RST (reset flag) packets. The Transmission Control Protocol (TCP is one of the core protocols of the Internet Protocol Suite.

Multitracker

Another unofficial feature is an extension to the BitTorrent metadata format proposed by John Hoffman[29] and implemented by several indexing websites. It allows the use of multiple trackers per file, so if one tracker fails, others can continue supporting file transfer. It is implemented in several clients, such as BitComet, BitTornado, KTorrent and µTorrent. BitComet (originally named SimpleBT client from versions 011 to 0 BitTornado is a BitTorrent client. It is developed by John Hoffman who also created its predecessor Shadow's Experimental Client. KTorrent is a BitTorrent client written in C++ for KDE using the Qt user interface toolkit Trackers are placed in groups, or tiers, with a tracker randomly chosen from the top tier and tried, moving to the next tier if all the trackers in the top tier fail.

Torrents with multiple trackers[30] can decrease the time it takes to download a file, but also has a few consequences:

Decentralized keyword search

Even with distributed trackers, a third party is still required to find a specific torrent. This is usually done in the form of a direct hyperlink from the website of the content owner or through indexing websites like The Pirate Bay. The Pirate Bay is a Swedish Website that indexes and tracks BitTorrent ("torrent" files

In May 2007 Cornell University published a paper proposing a new approach to searching a peer-to-peer network for inexact strings[31] which could replace the functionality of a central indexing site. May 2007 is the fifth month of that year It began on a Tuesday and 31 days later ended on a Thursday. A year later, the same team implemented the system as a plugin for Azureus called Cubit[32] and published a follow-up paper reporting its success[33].

Implementations

Main article: Comparison of BitTorrent software

Because of the open nature of the protocol, many clients have been developed that support numerous platforms and written using various programming languages. A BitTorrent client is a program that manages torrent downloads The official client is also named BitTorrent. BitTorrent is a Peer-to-peer program developed by Bram Cohen and BitTorrent Inc

Some clients, like Torrentflux, can be run straight from a server, allowing hosting companies to offer speeds unavailable to most users. TorrentFlux is a free and Open source multi-user GUI for BitTornado. Sites such as Torrent2FTP offer services to download torrents and then make them available to the customer on a FTP server.

Opera Software now incorporates BitTorrent downloads through its popular browser software[34], as does Wyzo. Opera Software ( is a Norwegian corporation primarily known for its Opera family of web browsers WYZO (965 is an FM Radio station Licensed to Portage Michigan, It is currently branded as Kalamazoo Country Y96

An increasing number of hardware devices are being made to support BitTorrent. These include routers and NAS devices, as well as anything capable of running OpenWrt (routers) or Openslug (NAS). OpenWrt is a Linux -based Firmware program for embedded devices such as Residential gateways Support was originally limited to the

Development

An as-yet (2 February 2008) unimplemented unofficial feature is Similarity Enhanced Transfer (SET), a technique for improving the speed at which peer-to-peer file sharing and content distribution systems can share data. Events 962 - Translatio imperii: Pope John XII crowns Otto I Holy Roman Emperor, the first Holy Roman Emperor 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common Similarity-Enhanced Transfer ( SET) is a technique for improving the speed at which Peer-to-peer File sharing SET, proposed by researchers Pucha, Andersen, and Kaminsky, works by spotting chunks of identical data in files that are an exact or near match to the one needed and transferring these data to the client if the 'exact' data are not present. Their experiments suggested that SET will help greatly with less popular files, but not as much for popular data, where many peers are already downloading it. [35] Andersen believes that this technique could be immediately used by developers with the BitTorrent file sharing system. [36]

See also

Notes

  1. ^ Cohen, Bram (2001-07-02). This is a list of terms used when discussing BitTorrent clients, and in particular the BitTorrent protocol used by these clients Super seeding is a feature of some BitTorrent clients that attempts to minimize the amount of data which must be uploaded by the original seed until the first completion Segmented downloading (also known as multisource downloading swarming download can be a more efficient way of Downloading files from many peers at once See also Comparison of BitTorrent software Comparison of eDonkey software The magnet URI scheme is a draft open standard defining a URI scheme for magnet links, which are mainly used to reference resources available for download via Similarity-Enhanced Transfer ( SET) is a technique for improving the speed at which Peer-to-peer File sharing Simple file verification (SFV is a file format for storing CRC32 Checksums of files in order to verify the integrity of files Year 2001 ( MMI) was a Common year starting on Monday according to the Gregorian calendar. Events 310 - Pope Miltiades is elected 626 - In fear of assassination Li Shimin ambushes and kills his rival BitTorrent - a new P2P app. Yahoo eGroups. Retrieved on 2007-04-15. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 1450 - Battle of Formigny: Toward the end of the Hundred Years' War, the French attack and nearly annihilate English
  2. ^ Urvoy-Keller (December, 2006). Rarest First and Choke Algorithms Are Enough. imconf. net. Retrieved on 2007-11-10. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 1444 - Battle of Varna: The crusading forces of King Vladislaus III of Varna (aka Ulaszlo I of Hungary and Wladyslaw
  3. ^ a b Cohen, Bram (October, 2002). BitTorrent Protocol 1.0. BitTorrent. org. Retrieved on 2006-05-06. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 1527 - Spanish and German troops sack Rome; some consider this the end of the Renaissance.
  4. ^ a b Tamilmani, Karthik (2003-10-25). Year 2003 ( MMIII) was a Common year starting on Wednesday of the Gregorian calendar. Events 1147 - The Portuguese, under Afonso I, and Crusaders from England and Flanders conquer Lisbon after a Studying and enhancing the BitTorrent protocol. Stony Brook University. Retrieved on 2006-05-06. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 1527 - Spanish and German troops sack Rome; some consider this the end of the Renaissance.
  5. ^ See, for example, Why Bit Torrent at tasvideos.org
  6. ^ Sub Pop page on BitTorrent.com. Retrieved on 2006-12-13. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 1294 - Saint Celestine V abdicates the papacy after only five months Celestine hoped to return to his previous life ]
  7. ^ www.browntracker.net, the website used by Ween. Ween is an Alternative rock group formed in 1984 in New Hope Pennsylvania when Aaron Freeman and Mickey Melchiondo met in an eighth grade typing class Retrieved on 2006-12-13. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 1294 - Saint Celestine V abdicates the papacy after only five months Celestine hoped to return to his previous life
  8. ^ CBC to BitTorrent Canada's Next Great Prime Minister: (2008-03-19). 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common Events 1279 - A Mongolian victory in the Battle of Yamen ends the Song Dynasty in China. Retrieved on 2008-03-19. 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common Events 1279 - A Mongolian victory in the Battle of Yamen ends the Song Dynasty in China.
  9. ^ Rustad, Roger E. (2004-08-26). "MMIV" redirects here For the Modest Mouse album see " Baron von Bullshit Rides Again " Events 1071 - Battle of Manzikert: The Seljuk Turks defeat the Byzantine Army at Manzikert. Blog Torrent and Participatory Culture. Grep Law. Retrieved on 2006-05-09. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 1457 BC - Battle of Megiddo (15th century BC between Thutmose III and a large Canaanite coalition under the King of
  10. ^ Ellis, Leslie (May 8, 2006). BitTorrent’s Swarms Have a Deadly Bite On Broadband Nets. Multichannel News. Retrieved on 2006-05-08. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 589 - Reccared summons the Third Council of Toledo 1450 - Jack Cade's Rebellion: Kentishmen
  11. ^ Pasick, Adam (2004-11-04). "MMIV" redirects here For the Modest Mouse album see " Baron von Bullshit Rides Again " Events 1333 - Flood of the Arno River, causing massive damage in Florence as recorded by the Florentine chronicler Giovanni Villani LIVEWIRE - File-sharing network thrives beneath the radar. Yahoo! News. Retrieved on 2006-05-09. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 1457 BC - Battle of Megiddo (15th century BC between Thutmose III and a large Canaanite coalition under the King of
  12. ^ Sevcik, Peter (November 01, 2005). Peer-to-Peer Traffic: Another Internet Myth Is Born. Business Communication Review. Retrieved on 2006-05-09. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 1457 BC - Battle of Megiddo (15th century BC between Thutmose III and a large Canaanite coalition under the King of
  13. ^ uTorrent's FAQ page.
  14. ^ Worthington, David; Nate Mook (May 25, 2005). BitTorrent Creator Opens Online Search. BetaNews. Retrieved on 2006-05-09. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 1457 BC - Battle of Megiddo (15th century BC between Thutmose III and a large Canaanite coalition under the King of
  15. ^ The Piratebay is Down: Raided by the Swedish Police. TorrentFreak (31. 05. 2006). Retrieved on 2007-05-20. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 325 - The First Council of Nicaea &ndash the first Ecumenical Council of the Christian Church is held
  16. ^ Henderson, Maryanne (2006-03-21). Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 630 - Byzantine emperor Heraclius restores the True Cross to Jerusalem. Safenet (for HBO) Letter to Charter Communications - Part 2.jpg. Tallin Wordpress. Retrieved on 2007-04-22. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 1500 - Portuguese Navigator Pedro Álvares Cabral becomes the first European to sight Brazil.
  17. ^ Torkington, Nat (October 04, 2005). Events 610 - Heraclius arrives by ship from Africa at Constantinople, overthrows Byzantine Emperor Phocas Year 2005 ( MMV) was a Common year starting on Saturday (link displays full calendar of the Gregorian calendar. HBO Attacking BitTorrent. O'Reilly. com. Retrieved on 2007-04-22. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 1500 - Portuguese Navigator Pedro Álvares Cabral becomes the first European to sight Brazil.
  18. ^ Khashmir Sourceforge
  19. ^ HTTP-Based Seeding Specification (TXT). Retrieved on 2006-05-09. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 1457 BC - Battle of Megiddo (15th century BC between Thutmose III and a large Canaanite coalition under the King of
  20. ^ Gillmore, Steve. BitTorrent and RSS Create Disruptive Revolution EWeek. com, December 13, 2003. Events 1294 - Saint Celestine V abdicates the papacy after only five months Celestine hoped to return to his previous life Year 2003 ( MMIII) was a Common year starting on Wednesday of the Gregorian calendar. Retrieved on 2007-04-22. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 1500 - Portuguese Navigator Pedro Álvares Cabral becomes the first European to sight Brazil.
  21. ^ Raymond, Scott: Broadcatching with BitTorrent. scottraymond. net: 2003-12-16. Year 2003 ( MMIII) was a Common year starting on Wednesday of the Gregorian calendar. Events 755 - An Lushan revolts against Chancellor Yang Guozhong at Fanyang, initiating the An Shi Rebellion
  22. ^ Move Digital REST API. Move Digital. Retrieved on 2006-05-09. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 1457 BC - Battle of Megiddo (15th century BC between Thutmose III and a large Canaanite coalition under the King of Documentation.
  23. ^ Prodigem Enclosure Puller(pep.txt) (TXT). Prodigem. com. Retrieved on 2006-05-09. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 1457 BC - Battle of Megiddo (15th century BC between Thutmose III and a large Canaanite coalition under the King of via Internet Wayback Machine
  24. ^ Encrypting Bittorrent to take out traffic shapers. The Internet Archive ( IA) is a Nonprofit organization dedicated to maintaining an on-line Library and archive of Web and Torrentfreak. com (2006-02-05). Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 1576 - Henry of Navarre converts to Roman Catholicism in order to ensure his right to the throne of France. Retrieved on 2006-05-09. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 1457 BC - Battle of Megiddo (15th century BC between Thutmose III and a large Canaanite coalition under the King of
  25. ^ Comcast Throttles BitTorrent Traffic, Seeding Impossible, TorrentFreak, 17 August 2007
  26. ^ Comcast and Bittorrent Agree to Collaborate
  27. ^ Is Comcast's BitTorrent filtering violating the law?
  28. ^ Obama would make Comcast's interference with BitTorrent illegal, aides say
  29. ^ MULTITRACKER METADATA ENTRY SPECIFICATION (TXT). Bittornado. com. Retrieved on 2006-05-09. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 1457 BC - Battle of Megiddo (15th century BC between Thutmose III and a large Canaanite coalition under the King of
  30. ^ called MultiTorrents by indexing website myBittorrent.com
  31. ^ Hyperspaces for Object Clustering and Approximate Matching in Peer-to-Peer Overlays (PDF). Cornell University. Retrieved on 2008-05-26. 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common Events 451 - The Battle of Avarayr between Armenian rebels and the Sassanid Empire takes place
  32. ^ Cubit: Approximate Matching for Peer-to-Peer Overlays (HTML). Cornell University. Retrieved on 2008-05-26. 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common Events 451 - The Battle of Avarayr between Armenian rebels and the Sassanid Empire takes place
  33. ^ Approximate Matching for Peer-to-Peer Overlays with Cubit (PDF). Cornell University. Retrieved on 2008-05-26. 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common Events 451 - The Battle of Avarayr between Armenian rebels and the Sassanid Empire takes place
  34. ^ Anderson, Nate (February 1, 2007). Does network neutrality mean an end to BitTorrent throttling?. Ars Technica, LLC. Retrieved on 2007-02-09. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 474 - Zeno crowned as co-emperor of the Byzantine Empire.
  35. ^ Himabindu Pucha, David G. Andersen, Michael Kaminsky (April 2007). Exploiting Similarity for Multi-Source Downloads Using File Handprints. Purdue Univ. , Carnegie Mellon Univ. , Intel Research Pittsburgh. Retrieved on 2007-04-15. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 1450 - Battle of Formigny: Toward the end of the Hundred Years' War, the French attack and nearly annihilate English
  36. ^ Speed boost plan for file-sharing. BBC News (2007-04-12). Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 467 - Anthemius is elevated to Emperor of the Western Roman Empire. Retrieved on 2007-04-21. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 753 BC - Romulus and Remus found Rome ( traditional date)

References

External links

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