See also: File sharing | Hash | Link
A unique link to a specific file on a file sharing network or system. It does not link to a specific location like hyperlinks do, instead merely containing the near-unique hash of the file that should be downloaded. Most file sharing programs generate the hash of the file on startup using standard MD4 or MD5 algorithms.
The user’s file sharing client then tries to first locate the file by searching for its hash (unless the location is deliberately hidden, such as in Freenet) and then download it. This system is only slightly different from BitTorrent, where the process requires only the .torrent file and the very simple program install.
Hash-links are used by many web sites such as The Pirate Bay and Musicdonkey.Net to validate the files on file sharing networks that support them.
eD2K
Example link for eDonkey2000 (modified to not work):
ed2k://|file|Monty-Pythons-Life-Of-Brian-(1979).ShareReactor.avi|733011968|4ed11dd0ec6db2f89670|
^- filename
^- size
^- hash
Other Hashes
Some Gnutella vendors have experimented with “gnut:” or “gnutella:” links, and an open standard for project-neutral links has been proposed called MAGNET-URI. Those links look like this:
magnet:?xt=urn:sha1:3TYQMTFEXP2G64G2SGVNBLIKCAXYHSS6&dn=[JVE]-EdTheSock-Avril-Lavigne.mov
Others include the TTH magnet for [[DC++]] (ver >0.307) and the SHA1 magnets for many program using SHA1 magnets like a few Gnutella clients, Piolet, Rockitnet, etc)
Hash links have also been hacked into FastTrack (Kazaa, KaZaA Lite, Grokster) via a utility called sig2dat or another called P2PFastClick.
More discussion of the differences between different systems’ hash-links is available on a Bitzi help page.
TakeDown.NET -> “Hash-Link”