of the second file] Tiger Tree Hash (TTH) These hashes are used on Direct Connect and G2 (Gnutella2), among others. xt=urn:tree:tiger:[ TTH Hash (Base32) ] Secure Hash Algorithm 1 (SHA-1) These hash sums are used on gnutella and G2 (Gnutella2). xt=urn:sha1:[ SHA-1 Hash (Base32) ] 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:[ SHA-1 Hash (Base32) ].[ TTH Hash (Base32) ] ED2K (eDonkey2000) hash These hash sums are used on eDonkey2000. xt=urn:ed2k:[ ED2K Hash (Hex) ] 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:[ aich Hash (Base32) ] Kazaa hash Used on FastTrack, these hash sums are vulnerable to hash collision attacks. xt=urn:kzhash:[ Kazaa Hash (Hex) ] 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. xt=urn:btih:[ BitTorrent Info Hash (Hex) ] 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 xt=urn:btmh:[ BitTorrent Info Hash (Hex) ] Message Digest 5 (MD5) Supported by G2 (Gnutella2), such hashes are vulnerable to hash collision attacks. xt=urn:md5:[ MD5 Hash (Hex) ] 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 as well as G2 applications. xs=http://[Client Address]:[Port of client]/uri-res/N2R?[ URN containing a file hash ] 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