Bitcoin is a peer-to-peer electronic cash system that is completely decentralized, without the need for a central server or trusted parties. Users hold the crypto keys to their own money and transact directly with each other, with the help of a P2P network to check for double-spending.
Forban is a P2P file sharing application for link-local and local area networks. Forban works independently from the Internet and uses only the local area capabilities to announce, discover, search, or share files. Forban relies on HTTP and is opportunistic, meaning that it replicates any files of interest seen in its proximity. The Forban protocols are minimalistic to ease the production of other implementations.
uhub is a high performance peer-to-peer hub for the ADC network. Its low memory footprint allows it to handle several thousand users on high-end servers, or a small private hub on embedded hardware. It uses the ADC protocol, and is compatible with DC++, jUCy, and other ADC clients.
TomP2P is a P2P-based high performance key-value pair storage library. Each peer has a table (either disk-based or memory-based) to store its values. A single value can be queried or updated with a secondary key. The underlying communication framework uses Java NIO to handle many concurrent connections.
filegive easily sends or receives files point-to-point, with authentication and ciphering, and the other side only needs a Web browser. No third party server is involved in the transfer. It can use common NAT traversal protocols like uPnP and NAT-PMP, manually forwarded ports, or a public ssh server.
pwnat, pronounced "poe-nat", is a tool that allows any number of clients behind NAT gateways to communicate with a server behind a separate NAT with no port forwarding and no DMZ setup on any routers in order to directly communicate with each other. The server does not need to know anything about the clients trying to connect, nor does it need to communicate with any other hosts in order to initiate the communication. Simply put, this is a proxy server that works behind a NAT, even when the client is behind a NAT. There is no middle man, no proxy, no third party, no UPnP required, no spoofing, and no DNS tricks. More importantly, the client can then connect to any host or port on any remote host or to a fixed host and port decided by the server.
KTorrent is a BitTorrent application that allows you to download and share files using the BitTorrent protocol. Key features include queuing of torrents, global and per-torrent speed limits, previewing of certain file types, importing of partially or fully downloaded files, file prioritization for multi-file torrents, selective downloading for multi-file torrents, kick/ban peers with an additional IP Filter dialog for list/edit purposes, UDP tracker support, support for private trackers and torrents, support for µTorrent's peer exchange, support for protocol encryption (compatible with Azureus), support for creating tracker-less torrents, support for distributed hash tables (DHT), support for UPnP to automatically forward ports on a LAN with dynamic assigned hosts, support for webseeds, scripting support via Kross, and interprocess control via DBus interface.
Although widely used, currently popular peer-to-peer (P2P) applications offer no user privacy. By design, services like BitTorrent and Gnutella share data with anyone that asks for it, allowing a third-party to systematically monitor user behavior. As a result, using a P2P network means that your online activities become public knowledge. OneSwarm is a peer-to-peer tool that provides users with explicit control over their privacy by letting them determine how data is shared. Instead of sharing data indiscriminately, data shared with OneSwarm can be made public, shared with friends, shared with some friends but not others, and so forth.