BitTorrent

BitTorrent is a peer-to-peer file sharing protocol designed to distribute large data sets efficiently across the Internet. Created by Bram Cohen in 2001, it operates as an open standard that reduces the burden on any single source by leveraging the combined upload bandwidth of all participants in a swarm.

Files are split into pieces, and a torrent file or magnet link contains metadata and information needed to locate other peers. Peers download missing pieces from multiple partners while uploading pieces they already have. A tracker coordinates peers, while distributed technologies such as DHT (distributed hash table) and peer exchange enable discovery without a central server. The group of active sharing users is called a swarm; when a peer completes the file, it continues to seed to assist others. Magnet links identify content by its hash rather than a file, enabling decentralized discovery.

BitTorrent clients implement the protocol; popular examples include qBittorrent, Transmission, Deluge, uTorrent, and the BitTorrent official client. Core features include piece verification via hashes, optional encryption, bandwidth throttling, and prioritization. The protocol supports trackers, DHT, PEX, and magnet links, and has evolved with extensions and newer layouts to improve efficiency and resilience.

Use of BitTorrent enables rapid distribution of large files with reduced origin server load, and is employed for legitimate software distributions, media releases, and research datasets. Nevertheless, it is also associated with copyright infringement, leading to legal and policy debates and the importance of using legitimate sources and respecting rights.