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Magnet is a URI scheme that defines the format of magnet links, a
( Base32) ]
; SHA-1, Secure Hash Algorithm 1 (SHA-1): These hash sums are used on
( Base32) ]
; BitPrint: Such hash sums consist of an SHA-1 Hash, followed by a TTH Hash, delimited by a point; they are used on
Magnet is a URI scheme that defines the format of magnet links, a de facto standard
A ''de facto'' standard is a custom or convention that has achieved a dominant position by public acceptance or market forces (for example, by early entrance to the market). is a Latin phrase (literally "in fact"), here meaning "in practice but ...
for identifying files ( URN) by their content, via cryptographic hash value rather than by their location.
Although magnet links can be used in a number of contexts, they are particularly useful in peer-to-peer file sharing
Peer-to-peer file sharing is the distribution and sharing of digital media using peer-to-peer (P2P) networking technology. P2P file sharing allows users to access media files such as books, music, movies, and games using a P2P software program th ...
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
File sharing is the practice of distributing or providing access to digital media, such as computer programs, multimedia (audio, images and video), documents or electronic books. Common methods of storage, transmission and dispersion include r ...
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.
History
The standard for Magnet URIs was developed by Bitzi in 2002, partly as a "vendor- and project-neutral generalization" of theed2k: and freenet: URI schemes used by eDonkey2000
eDonkey2000 (nicknamed "ed2k") was a peer-to-peer file sharing application developed by US company MetaMachine ( Jed McCaleb and Sam Yagan), using the Multisource File Transfer Protocol. This client supports both the eDonkey2000 network and t ...
and Freenet
Freenet is a peer-to-peer platform for censorship-resistant, anonymous communication. It uses a decentralized distributed data store to keep and deliver information, and has a suite of free software for publishing and communicating on the Web ...
, respectively, and attempts to follow official IETF
The Internet Engineering Task Force (IETF) is a standards organization for the Internet and is responsible for the technical standards that make up the Internet protocol suite (TCP/IP). It has no formal membership roster or requirements and ...
URI standards as closely as possible. BitTorrent introduced the btmh: protocol in 2020 as part of its BitTorrent v2 changes.
Format
Magnet URIs consist of a series of one or more parameters, the order of which is not significant, formatted in the same way asquery string
A query string is a part of a uniform resource locator (URL) that assigns values to specified parameters. A query string commonly includes fields added to a base URL by a Web browser or other client application, for example as part of an HTML, cho ...
s that ordinarily terminate HTTP
The Hypertext Transfer Protocol (HTTP) is an application layer protocol in the Internet protocol suite model for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide Web, ...
URLs.
The following parameters are supported:
The standard also allows for application-specific experimental parameters, which must begin with "x".
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. 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.
:magnet:?xt.1= URN of the first file"> URN of the first filext.2= URN of the second file/code>
; Tiger Tree Hash (TTH): These hashes are used on Direct Connect and G2 (Gnutella2), among others.
:xt=urn:tree:tiger : TTH hash sum">Hash
Hash, hashes, hash mark, or hashing may refer to:
Substances
* Hash (food), a coarse mixture of ingredients
* Hash, a nickname for hashish, a cannabis product
Hash mark
*Hash mark (sports), a marking on hockey rinks and gridiron football field ...
gnutella
Gnutella is a peer-to-peer network protocol. Founded in 2000, it was the first decentralized peer-to-peer network of its kind, leading to other, later networks adopting the model.
In June 2005, Gnutella's population was 1.81 million computer ...
and G2 (Gnutella2).
:xt=urn:sha1 : SHA-1 hash function">Hash
Hash, hashes, hash mark, or hashing may refer to:
Substances
* Hash (food), a coarse mixture of ingredients
* Hash, a nickname for hashish, a cannabis product
Hash mark
*Hash mark (sports), a marking on hockey rinks and gridiron football field ...
gnutella
Gnutella is a peer-to-peer network protocol. Founded in 2000, it was the first decentralized peer-to-peer network of its kind, leading to other, later networks adopting the model.
In June 2005, Gnutella's population was 1.81 million computer ...
and G2 (Gnutella2).
:xt=urn:bitprint : SHA-1 hash function">Hash
Hash, hashes, hash mark, or hashing may refer to:
Substances
* Hash (food), a coarse mixture of ingredients
* Hash, a nickname for hashish, a cannabis product
Hash mark
*Hash mark (sports), a marking on hockey rinks and gridiron football field ...
( Base32) ]. TTH hash sum">Hash
Hash, hashes, hash mark, or hashing may refer to:
Substances
* Hash (food), a coarse mixture of ingredients
* Hash, a nickname for hashish, a cannabis product
Hash mark
*Hash mark (sports), a marking on hockey rinks and gridiron football field ...
( Base32) ]
; EDonkey network#Hash identification, ED2K (eDonkey2000) hash: These hash sums are used on eDonkey2000
eDonkey2000 (nicknamed "ed2k") was a peer-to-peer file sharing application developed by US company MetaMachine ( Jed McCaleb and Sam Yagan), using the Multisource File Transfer Protocol. This client supports both the eDonkey2000 network and t ...
.
:xt=urn:ed2k :[ EDonkey network#Hash identification, ED2K hash sum, Hash (Hex
Hex or HEX may refer to:
Magic
* Hex, a curse or supposed real and potentially supernaturally realized malicious wish
* Hex sign, a barn decoration originating in Pennsylvania Dutch regions of the United States
* Hex work, a Pennsylvania Dutch ...
) ]
; AICH, Advanced Intelligent Corruption Handler (AICH): Not formal URNs for Magnet links, such hash sums are used by eDonkey2000
eDonkey2000 (nicknamed "ed2k") was a peer-to-peer file sharing application developed by US company MetaMachine ( Jed McCaleb and Sam Yagan), using the Multisource File Transfer Protocol. This client supports both the eDonkey2000 network and t ...
to restore and control the integrity of downloading and already downloaded files.
:xt=urn:aich : aich.html" ;"title="AICH, aich">AICH, aich hash sum, Hash ( Base32) /code>
; Kazaa hash: Used on FastTrack
FastTrack is a peer-to-peer (P2P) protocol that was used by the Kazaa, Grokster, iMesh and Morpheus file sharing programs. FastTrack was the most popular file sharing network in 2003, and used mainly for the exchange of music mp3 files. The netwo ...
, these hash sums are vulnerable to hash collision attacks.
:xt=urn:kzhash :[ Kazaa hash sum, Hash (Hex
Hex or HEX may refer to:
Magic
* Hex, a curse or supposed real and potentially supernaturally realized malicious wish
* Hex sign, a barn decoration originating in Pennsylvania Dutch regions of the United States
* Hex work, a Pennsylvania Dutch ...
) ]
; BitTorrent info hash (BTIH): These are hex-encoded SHA-1 hash sums of the "info" sections of BitTorrent (protocol)#Creating and publishing torrents, 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.
:xt=urn:btih :[ [ BitTorrent Info hash sum, Hash (Hex
Hex or HEX may refer to:
Magic
* Hex, a curse or supposed real and potentially supernaturally realized malicious wish
* Hex sign, a barn decoration originating in Pennsylvania Dutch regions of the United States
* Hex work, a Pennsylvania Dutch ...
) ]
: Some clients require Base32 of info_hash (e.g., Vuze).
; BitTorrent info hash v2 (BTMH): BitTorrent, BitTorrent v2 replaces the SHA-1, obsolete SHA-1 hash with a SHA-256
SHA-2 (Secure Hash Algorithm 2) is a set of cryptographic hash functions designed by the United States National Security Agency (NSA) and first published in 2001. They are built using the Merkle–Damgård construction, from a one-way compressi ...
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
:xt=urn:btmh :[ [ BitTorrent Info hash sum, Hash (Hex
Hex or HEX may refer to:
Magic
* Hex, a curse or supposed real and potentially supernaturally realized malicious wish
* Hex sign, a barn decoration originating in Pennsylvania Dutch regions of the United States
* Hex work, a Pennsylvania Dutch ...
) ]
; MD5, Message Digest 5 (MD5): Supported by G2 (Gnutella2), such hashes are vulnerable to hash collision attacks.
:xt=urn:md5 : MD5 hash sum, Hash (Hex
Hex or HEX may refer to:
Magic
* Hex, a curse or supposed real and potentially supernaturally realized malicious wish
* Hex sign, a barn decoration originating in Pennsylvania Dutch regions of the United States
* Hex work, a Pennsylvania Dutch ...
) ]
Web links to the file
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 -based link is used by gnutella
Gnutella is a peer-to-peer network protocol. Founded in 2000, it was the first decentralized peer-to-peer network of its kind, leading to other, later networks adopting the model.
In June 2005, Gnutella's population was 1.81 million computer ...
as well as G2 applications.
:xs=http:// lient Address ort of clienturi-res/N2R?URN containing a file hash sum">hash
Hash, hashes, hash mark, or hashing may refer to:
Substances
* Hash (food), a coarse mixture of ingredients
* Hash, a nickname for hashish, a cannabis product
Hash mark
*Hash mark (sports), a marking on hockey rinks and gridiron football field ...
]
: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://ub address
UB or Ub may refer to:
Organizations
* Basel University Library, german: Bibliothek der Universität Basel, abbreviated UB.
* UltimateBet, a defunct online poker site
*Ungermann-Bass, a computer networking company in California
*United Biscuits, ...
ub port
UB or Ub may refer to:
Organizations
*Basel University Library, german: Bibliothek der Universität Basel, abbreviated UB.
* UltimateBet, a defunct online poker site
*Ungermann-Bass, a computer networking company in California
*United Biscuits, ...
/code>
;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
A BitTorrent tracker is a special type of server that assists in the communication between peers using the BitTorrent protocol.
In peer-to-peer file sharing, a software client on an end-user PC requests a file, and portions of the requested f ...
.
:xs=http://cache.freebase.be/ SHA-1 hash sum">hash
Hash, hashes, hash mark, or hashing may refer to:
Substances
* Hash (food), a coarse mixture of ingredients
* Hash, a nickname for hashish, a cannabis product
Hash mark
*Hash mark (sports), a marking on hockey rinks and gridiron football field ...
]
;Reference to an eD2k source
:xs=ed2kftp://[client address]:[client port]/[ed2k hash]/[file size]/
Supplement format (x.)
For experimental and self-complementing informal options, the prefix followed by a chosen suffix letter can be used. These names are guaranteed to never be standardized.
:x.ame of the new parameter #REDIRECT AME #REDIRECT AME #REDIRECT AME
{{redirect category shell, {{R from other capitalisation{{R from ambiguous page ...
{{redirect category shell, {{R from other capitalisation{{R from ambiguous page ...
{{redirect category shell, ...
ata of the new parameter (URL encoded)">URL.html" ;"title="ata of the new parameter (URL">ata of the new parameter (URL encoded)/code>
Clients
See also
* BitTorrent
* Burnbit
* ed2k URI scheme
* InterPlanetary File System
* Metalink
* Named data networking
* Peer-to-peer
Explanatory notes
References
External links
* , an early definition of the format (last update 2002)
CHK
Freeware checksum utility with SHA1-Base32 and ED2K support
* , an open source
Open source is source code that is made freely available for possible modification and redistribution. Products include permission to use the source code, design documents, or content of the product. The open-source model is a decentralized sof ...
command-line tool, which can calculate magnet links
{{DEFAULTSORT:Magnet Uri Scheme
File sharing
URI schemes