Peer-to-peer networking with BitTorrent
Peer-to-peer networking has received a lot of attention due to the battles with the music and movie industries. Despite many beliefs it is not a new concept but, in its simplest form, has existed for over four decades and can be traced back to the original implementation of the Internet. BitTorrent is a distributed peer-to-peer system that uses a symmetric (tit-for-tat) transferring model in an attempt to reach Pareto efficiency. Its protocol employs various mechanisms and algorithms in a continuous effort to try to ensure that there are no other variations in the network arrangement which will make every downloader at least as well off and at least one downloader strictly better off. In its original implementation, BitTorrent bases its operation around the concept of a torrent file, a centralized tracker and an associated swarm of peers. The centralized tracker provides the different entities with an address list over available peers. Later improvements try to remove the weakness of a single point of failure (the tracker), by implementing a new distributed tracker solution.
Andrew Orr is a University of Manitoba Computer Science graduate working in vulnerability research and exploit development. He once read a paper on BitTorrent, and is not very good at writing bios. You can find him on Twitter as @xorrbit.