Although magnet links can be used in a number of contexts, they are particularly useful in peer-to-peer file sharing networks because they allow resources to be referred to without the need for a continuously available host, and can be generated by anyone who already has the file, without the need for a central authority to issue them. This makes them popular for use as "guaranteed" search terms within the file sharing community where anyone can distribute a magnet link to ensure that the resource retrieved by that link is the one intended, regardless of how it is retrieved.
The standard for Magnet URIs was developed by Bitzi in 2002, partly as a "vendor- and project-neutral generalization" of the ed2k: and freenet: URI schemes used by eDonkey2000 and Freenet, respectively, and attempts to follow official IETFURI standards as closely as possible. BitTorrent introduced the btmh: protocol in 2020 as part of its BitTorrent v2 changes.[1]
Format
Magnet URIs consist of a series of one or more parameters, the order of which is not significant, formatted in the same way as query strings that ordinarily terminate HTTP URLs.
URN containing file hash. This is the most crucial part of the magnet link, and is used to find and verify the specified file. The URN is specific to the protocol, so a file hash URN under btih (BitTorrent) would be completely different from the file hash URN for ed2k
Refers to a direct download from a web server. Regarded as only a fall-back source in case a client is unable to locate and/or download the linked-to file in its supported P2P network(s)
Either an HTTP (or HTTPS, FTP, FTPS, etc.) download source for the file pointed to by the Magnet link, the address of a P2P source for the file or the address of a hub (in the case of DC++), by which a client tries to connect directly, asking for the file and/or its sources. This field is commonly used by P2P clients to store the source, and may include the file hash.
xs=http://[Client Address]:[Port of client]/uri-res/N2R?[ URN containing a file hash ]
Lists specific files torrent clients should download,[5] indicated as individual or ranges (inclusive) of file indexes.
so=0,2,4,6-8
x.pe
PEer
Specifies fixed peer addresses to connect to. Used to bootstrap discovery of peers in the absence of (e.g.) trackers or DHT.[3]
x.pe=hostname:port
x.pe=ipv4-literal:port
x.pe=[ipv6-literal]:port
The standard also allows for application-specific experimental parameters, which must begin with "x".[citation needed]
Exact Topic (xt)
The xt parameter specifies the URN for a given p2p protocol. Its purpose is to provide a search parameter for finding the metadata to the torrent. This effectively acts as a replacement to a .torrent file, which itself contains the torrent metadata, by instead searching the p2p network (using the URN) for that metadata. Each protocol handles a URN uniquely; for example, xt=urn:btih:FFC7E738EAA4CD4ECF51EC6FD669C6CDE2C281A8 uses the btih (BitTorrent v1 protocol), so a BitTorrent client can take the hash and lookup the torrent's metadata in the BitTorrent DHT.[6] In the case of DHT the client searches through a set of pre-known nodes and requests the metadata for an infohash; those nodes will make the same request to other known nodes until eventually a swarm is found and returned.
xt also allows for a group setting. Multiple files can be included by adding a count number preceded by a dot (".") to each link parameter.[citation needed]
magnet:?xt.1=[ URN of the first file]&xt.2=[ URN of the second file]
Not formal URNs for Magnet links, such hash sums are used by eDonkey2000 to restore and control the integrity of downloading and already downloaded files.
These are hex-encoded SHA-1 hash sums of the "info" sections of BitTorrent metafiles as used by BitTorrent to identify downloadable files or sets of files. For backwards compatibility with existing links, clients should also support the Base32 encoded version of the hash.[3]
Some clients require Base32 of info_hash (e.g., Vuze).
BitTorrent info hash v2 (BTMH)
BitTorrent v2 replaces the obsolete SHA-1 hash with a SHA-256 info hash. The v2 info-hash is given a new prefix (btmh) to allow for torrents that can participate in both v1 and v2 swarms[7]
There are two types of download links that a Magnet link can include as a direct or backup source.
"as" ("acceptable source")
Most clients treat "as" as equal to the "xs" token when it comes to priority, and ignore the timeout before contacting "as" sources denoted by the specs.
Content-Addressable Web URL
This type of RFC 2168-based link is used by gnutella as well as G2 applications.[8]
xs=http://[Client Address]:[Port of client]/uri-res/N2R?[ URN containing a file hash ]
Link to a DirectConnect hub to find sources for a file
This type of link connects a DirectConnect client immediately to the hub in question.
xs=dchub://[hub address]:[hub port]
Reference to a web-based source cache for a file on Gnutella2
In this case, the included link points, not to a client IP or direct source, but to a source cache which stores the IPs of other clients contacting it to download the same file. Once a client connects to the cache, it is served IPs for alternate sources, while its own IP is stored within the cache and forwarded to the next one connecting to the cache. This system operates similar to a BitTorrent tracker.
For experimental and self-complementing informal options, the prefix x. followed by a chosen suffix letter can be used. These names are guaranteed to never be standardized.
x.[name of the new parameter]=[data of the new parameter (URL encoded)][citation needed]
^"BitTorrent v2". BitTorrent. from the original on 30 October 2020. Retrieved 7 September 2020.
^ ab"magnet-test.c in trunk/libtransmission; Revision 9531". Transmission. from the original on 2012-02-17. Retrieved 2012-02-04.
^ abcd"BitTorrent Enhancement Proposal 9: Extension for Peers to Send Metadata Files". bittorrent.org (published 2008-01-31). 2017-03-26. from the original on 2022-10-10. Retrieved 2022-11-04.
^"libtorrent/magnet_uri.cpp at 64817e0e8793d0875fc10245de52ffb2540a223d · arvidn/libtorrent". libtorrent. from the original on 2022-11-04. Retrieved 2022-11-04 – via GitHub.
^"BitTorrent Enhancement Proposal 53: Magnet URI extension - Select specific file indices for download". BitTorrent.org. 2017-06-06. from the original on 2022-10-10. Retrieved 2022-11-04.
^"BitTorrent v2". libbittorrent.org. libbittorrent. 2020-09-07. from the original on 2022-10-22. Retrieved 2022-11-05.
^Chapweske, Justin (November 29, 2001). "HTTP Extensions for a Content-Addressable Web". www-talk. W3C. from the original on July 28, 2011. Retrieved November 7, 2010.
^"v1.74 Core Improve: support ws parameter in Magnet URI, to add web seed". bitcomet. bitcomet. from the original on 2021-04-10. Retrieved 2021-04-07.
^"magnet.c in trunk/libtransmission; Revision 9979". Transmission. from the original on 2012-02-17. Retrieved 2012-02-04.
^"magnet.c in libtransmission: Commit 5c3fd1b5ccc3a8c4ab68e2c56861df31dd1c720a". Transmission. from the original on 2021-09-04. Retrieved 2021-09-04.
External links
Magnet-URI Project on SourceForge, an early definition of the format (last update 2002)
CHK Freeware checksum utility with SHA1-Base32 and ED2K support
RHash on SourceForge, an open source command-line tool, which can calculate magnet links
May 02, 2023
magnet, scheme, this, article, multiple, issues, please, help, improve, discuss, these, issues, talk, page, learn, when, remove, these, template, messages, this, article, needs, additional, citations, verification, please, help, improve, this, article, adding,. This article has multiple issues Please help improve it or discuss these issues on the talk page Learn how and when to remove these template messages This article needs additional citations for verification Please help improve this article by adding citations to reliable sources Unsourced material may be challenged and removed Find sources Magnet URI scheme news newspapers books scholar JSTOR January 2015 Learn how and when to remove this template message This article may require cleanup to meet Wikipedia s quality standards The specific problem is The lists of examples should be better organized the layout is too haphazard Please help improve this article if you can May 2012 Learn how and when to remove this template message This article may be too technical for most readers to understand Please help improve it to make it understandable to non experts without removing the technical details December 2014 Learn how and when to remove this template message Learn how and when to remove this template message Magnet is a URI scheme that defines the format of magnet links a de facto standard for identifying files URN by their content via cryptographic hash value rather than by their location Rounded magnet icon used on The Pirate Bay Although magnet links can be used in a number of contexts they are particularly useful in peer to peer file sharing networks because they allow resources to be referred to without the need for a continuously available host and can be generated by anyone who already has the file without the need for a central authority to issue them This makes them popular for use as guaranteed search terms within the file sharing community where anyone can distribute a magnet link to ensure that the resource retrieved by that link is the one intended regardless of how it is retrieved Contents 1 History 2 Format 2 1 Exact Topic xt 2 2 Web links to the file 2 3 Supplement format x 3 Clients 4 See also 5 Explanatory notes 6 References 7 External linksHistory EditThe standard for Magnet URIs was developed by Bitzi in 2002 partly as a vendor and project neutral generalization of the ed2k and freenet URI schemes used by eDonkey2000 and Freenet respectively and attempts to follow official IETF URI standards as closely as possible BitTorrent introduced the btmh protocol in 2020 as part of its BitTorrent v2 changes 1 Format EditMagnet URIs consist of a series of one or more parameters the order of which is not significant formatted in the same way as query strings that ordinarily terminate HTTP URLs The following parameters are supported 2 3 Parameter Name Descriptionxt Exact Topic URN containing file hash This is the most crucial part of the magnet link and is used to find and verify the specified file The URN is specific to the protocol so a file hash URN under btih BitTorrent would be completely different from the file hash URN for ed2k xt urn btih c12fe1c06bba254a9dc9f519b335aa7c1367a88adn Display Name A filename to display to the user for convenience xl eXact Length The file size in bytestr Address TRacker Tracker URL used to obtain resources for BitTorrent downloads without a need for DHT support 3 The value must be URL encoded tr http 3A 2F 2Fexample org 2Fannouncews Web Seed The payload data served over HTTP S as citation needed Acceptable Source Refers to a direct download from a web server Regarded as only a fall back source in case a client is unable to locate and or download the linked to file in its supported P2P network s as web link to file URL encoded xs citation needed eXact Source Either an HTTP or HTTPS FTP FTPS etc download source for the file pointed to by the Magnet link the address of a P2P source for the file or the address of a hub in the case of DC by which a client tries to connect directly asking for the file and or its sources This field is commonly used by P2P clients to store the source and may include the file hash xs http Client Address Port of client uri res N2R a href Uniform Resource Name html title Uniform Resource Name URN a containing a file a href Hash sum html class mw redirect title Hash sum hash a xs http 192 0 2 27 6346 uri res N2R urn sha1 FINYVGHENTHSMNDSQQYDNLPONVBZTICFkt citation needed Keyword Topic Specifies a string of search keywords to search for in P2P networks rather than a particular file kt martin luther king mp3mt citation needed Manifest Topic Link to the metafile that contains a list of magneto MAGMA MAGnet MAnifest i e a link to a list of links mt http example org all my favorites rss mt urn sha1 3I42H3S6NNFQ2MSVX7XZKYAYSCX5QBYJso 4 Select Only Lists specific files torrent clients should download 5 indicated as individual or ranges inclusive of file indexes so 0 2 4 6 8x pe PEer Specifies fixed peer addresses to connect to Used to bootstrap discovery of peers in the absence of e g trackers or DHT 3 x pe hostname port x pe ipv4 literal port x pe ipv6 literal portThe standard also allows for application specific experimental parameters which must begin with x citation needed Exact Topic xt Edit The xt parameter specifies the URN for a given p2p protocol Its purpose is to provide a search parameter for finding the metadata to the torrent This effectively acts as a replacement to a torrent file which itself contains the torrent metadata by instead searching the p2p network using the URN for that metadata Each protocol handles a URN uniquely for example xt urn btih FFC7E738EAA4CD4ECF51EC6FD669C6CDE2C281A8 uses the btih BitTorrent v1 protocol so a BitTorrent client can take the hash and lookup the torrent s metadata in the BitTorrent DHT 6 In the case of DHT the client searches through a set of pre known nodes and requests the metadata for an infohash those nodes will make the same request to other known nodes until eventually a swarm is found and returned xt also allows for a group setting Multiple files can be included by adding a count number preceded by a dot to each link parameter citation needed magnet xt 1 a href Uniform Resource Name html title Uniform Resource Name URN a of the first file amp xt 2 URN of the second file Tiger Tree Hash TTH These hashes are used on Direct Connect and G2 Gnutella2 among others xt urn tree tiger a href Merkle tree html Tiger tree hash title Merkle tree TTH a a href Hash sum html class mw redirect title Hash sum Hash a a href Base32 html title Base32 Base32 a Secure Hash Algorithm 1 SHA 1 These hash sums are used on gnutella and G2 Gnutella2 xt urn sha1 a href SHA 1 html title SHA 1 SHA 1 a a href Hash function html title Hash function Hash a a href Base32 html title Base32 Base32 a BitPrint Such hash sums consist of an SHA 1 Hash followed by a TTH Hash delimited by a point they are used on gnutella and G2 Gnutella2 xt urn bitprint a href SHA 1 html title SHA 1 SHA 1 a a href Hash function html title Hash function Hash a a href Base32 html title Base32 Base32 a a href Merkle tree html Tiger tree hash title Merkle tree TTH a a href Hash sum html class mw redirect title Hash sum Hash a a href Base32 html title Base32 Base32 a ED2K eDonkey2000 hash These hash sums are used on eDonkey2000 xt urn ed2k a href EDonkey network html Hash identification title EDonkey network ED2K a a href Hash sum html class mw redirect title Hash sum Hash a a href Hexadecimal html title Hexadecimal Hex a Advanced Intelligent Corruption Handler AICH Not formal URNs for Magnet links such hash sums are used by eDonkey2000 to restore and control the integrity of downloading and already downloaded files xt urn aich a href AICH html class mw redirect title AICH aich a a href Hash sum html class mw redirect title Hash sum Hash a a href Base32 html title Base32 Base32 a Kazaa hash Used on FastTrack these hash sums are vulnerable to hash collision attacks xt urn kzhash a href Kazaa html title Kazaa Kazaa a a href Hash sum html class mw redirect title Hash sum Hash a a href Hexadecimal html title Hexadecimal Hex a BitTorrent info hash BTIH These are hex encoded SHA 1 hash sums of the info sections of BitTorrent metafiles as used by BitTorrent to identify downloadable files or sets of files For backwards compatibility with existing links clients should also support the Base32 encoded version of the hash 3 xt urn btih a href BitTorrent protocol html class mw redirect title BitTorrent protocol BitTorrent a Info a href Hash sum html class mw redirect title Hash sum Hash a a href Hexadecimal html title Hexadecimal Hex a Some clients require Base32 of info hash e g Vuze BitTorrent info hash v2 BTMH BitTorrent v2 replaces the obsolete SHA 1 hash with a SHA 256 info hash The v2 info hash is given a new prefix btmh to allow for torrents that can participate in both v1 and v2 swarms 7 xt urn btmh a href BitTorrent protocol html class mw redirect title BitTorrent protocol BitTorrent a Info a href Hash sum html class mw redirect title Hash sum Hash a a href Hexadecimal html title Hexadecimal Hex a Message Digest 5 MD5 Supported by G2 Gnutella2 such hashes are vulnerable to hash collision attacks xt urn md5 a href MD5 html title MD5 MD5 a a href Hash sum html class mw redirect title Hash sum Hash a a href Hexadecimal html title Hexadecimal Hex a Web links to the file Edit There are two types of download links that a Magnet link can include as a direct or backup source as acceptable source Most clients treat as as equal to the xs token when it comes to priority and ignore the timeout before contacting as sources denoted by the specs Content Addressable Web URL This type of RFC 2168 based link is used by gnutella as well as G2 applications 8 xs http Client Address Port of client uri res N2R a href Uniform Resource Name html title Uniform Resource Name URN a containing a file a href Hash sum html class mw redirect title Hash sum hash a xs http 192 0 2 27 6346 uri res N2R urn sha1 FINYVGHENTHSMNDSQQYDNLPONVBZTICF Link to a DirectConnect hub to find sources for a file This type of link connects a DirectConnect client immediately to the hub in question xs dchub hub address hub port Reference to a web based source cache for a file on Gnutella2 In this case the included link points not to a client IP or direct source but to a source cache which stores the IPs of other clients contacting it to download the same file Once a client connects to the cache it is served IPs for alternate sources while its own IP is stored within the cache and forwarded to the next one connecting to the cache This system operates similar to a BitTorrent tracker xs a rel nofollow class external free href http cache freebase be http cache freebase be a a href SHA 1 html title SHA 1 SHA 1 a a href Hash sum html class mw redirect title Hash sum hash a Reference to an eD2k source xs ed2kftp client address client port ed2k hash file size Supplement format x Edit For experimental and self complementing informal options the prefix x followed by a chosen suffix letter can be used These names are guaranteed to never be standardized x name of the new parameter data of the new parameter a href URL html title URL URL a encoded citation needed Clients EditClient dn xl xt tr xs as kt mt wsAMule Yes Yes urn ed2k No Un known Un known Un known Un known Un knownApexDC Yes Yes urn bitprint urn tree tiger No dchub Note 1 dchub Note 1 No No Un knownBitComet Yes Yes urn btih Yes Yes1 76 No No No Yes1 74 9 Bitflu Yes No urn btih Yes No No No No Un knownDeluge Yes No urn btih Yes No No No No Un knownEiskaltDC Yes Yes urn tree tiger urn bitprint urn btih Note 2 urn btmh Note 2 No dchub Note 1 adc Note 3 adcs Note 4 dchub Note 1 Yes No Un knownFlylinkDC Yes Yes urn tree tiger urn bitprint urn btih No dchub Note 1 adc Note 3 adcs Note 4 dchub Note 1 Yes No Un knowngtk gnutella Yes Yes urn sha1 No http push Yes Yes No Un knownKTorrent Yes No urn btih Yes No No No No Un knownLimeWire Yes Yes urn sha1 No http urn guid Un known No No Un knownMonoTorrent Yes Yes urn btih Yes No Yes No No Un knownmTorrent Yes No urn btih Yes No No No No YesqBittorrent Yes No urn btih Yes Un known Un known No No Un knownShareaza Yes Yes urn bitprint urn btih urn ed2k urn md5 urn sha1 urn tree tiger Yes Note 5 http ftp http ftp Same priority as xs Yes No Un knownTixati Yes Yes urn btih Yes Yes Yes Un known Un known YesTransmission 2 10 Yes No urn btih Yes No No No No Yes 11 Vuze Yes Yes urn btih urn sha1 Yes Yes5 7 5 0 Yes5 7 5 0 No No YesSee also EditBitTorrent Burnbit ed2k URI scheme InterPlanetary File System Metalink Named data networking Peer to peerExplanatory notes Edit a b c d e f dchub hubaddress hubport a b Passes link to external software a b adc hubaddress hubport a b adcs hubaddress hubport Since v2 5 1 0References Edit BitTorrent v2 BitTorrent Archived from the original on 30 October 2020 Retrieved 7 September 2020 a b magnet test c in trunk libtransmission Revision 9531 Transmission Archived from the original on 2012 02 17 Retrieved 2012 02 04 a b c d BitTorrent Enhancement Proposal 9 Extension for Peers to Send Metadata Files bittorrent org published 2008 01 31 2017 03 26 Archived from the original on 2022 10 10 Retrieved 2022 11 04 libtorrent magnet uri cpp at 64817e0e8793d0875fc10245de52ffb2540a223d arvidn libtorrent libtorrent Archived from the original on 2022 11 04 Retrieved 2022 11 04 via GitHub BitTorrent Enhancement Proposal 53 Magnet URI extension Select specific file indices for download BitTorrent org 2017 06 06 Archived from the original on 2022 10 10 Retrieved 2022 11 04 bep 0005 rst post bittorrent org Retrieved 2022 05 12 BitTorrent v2 libbittorrent org libbittorrent 2020 09 07 Archived from the original on 2022 10 22 Retrieved 2022 11 05 Chapweske Justin November 29 2001 HTTP Extensions for a Content Addressable Web www talk W3C Archived from the original on July 28 2011 Retrieved November 7 2010 v1 74 Core Improve support ws parameter in Magnet URI to add web seed bitcomet bitcomet Archived from the original on 2021 04 10 Retrieved 2021 04 07 magnet c in trunk libtransmission Revision 9979 Transmission Archived from the original on 2012 02 17 Retrieved 2012 02 04 magnet c in libtransmission Commit 5c3fd1b5ccc3a8c4ab68e2c56861df31dd1c720a Transmission Archived from the original on 2021 09 04 Retrieved 2021 09 04 External links EditMagnet URI Project on SourceForge an early definition of the format last update 2002 CHK Freeware checksum utility with SHA1 Base32 and ED2K support RHash on SourceForge an open source command line tool which can calculate magnet links Retrieved from https en wikipedia org w index php title Magnet URI scheme amp oldid 1150976031, wikipedia, wiki, book, books, library,
