FastTrack is apeer-to-peer (P2P)protocol that was used by theKazaa,[1][2]Grokster,[3]iMesh[4] andMorpheusfile sharing programs.[5] FastTrack was the most popular file sharing network in 2003, and used mainly for the exchange of musicMP3 files. The network had approximately 2.4 millionconcurrent users in 2003. It is estimated that the total number of users was greater than that ofNapster at its peak.[citation needed]
The FastTrack protocol and Kazaa were created and developed byEstonian programmers of BlueMoon Interactive headed byJaan Tallinn,[6] the same team that later createdSkype. After selling it toNiklas Zennström fromSweden andJanus Friis fromDenmark, it was introduced in March 2001 by theirDutch company Consumer Empowerment. It appeared during the end of the first generation ofP2P networks –Napster shut down in July of that year. There are three FastTrack-based networks, and they use mutuallyincompatible versions of the protocol. The most popularclients on each are Kazaa (and its variations), Grokster, and iMesh. For more information about the variouslawsuits surrounding Kazaa andSharman Networks, seeKazaa.
FastTrack usessupernodes to improvescalability.
To allow downloading from multiple sources, FastTrack employs theUUHashhashing algorithm. While UUHash allows very largefiles to bechecksummed in a short time, even on slow weakcomputers, it also allows for massivecorruption of a file to go unnoticed. Many people, as well as theRIAA, have exploited thisvulnerability to spread corrupt and fake files on the network.[7]
The FastTrack protocol usesencryption and was notdocumented by its creators. The first clients were allclosed source software. However, initialization data for the encryption algorithms is sent in the clear and nopublic key encryption is used, soreverse engineering was made comparatively easy. In 2003,open sourceprogrammers succeeded in reverse-engineering the portion of the protocol dealing with client-supernode communication, but the supernode-supernode communication protocol remains largely unknown.[citation needed]
The following programs are or have been FastTrack clients:
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