Winny is a Japanese peer-to-peer (P2P) file-sharing program developed by Isamu Kaneko, a research assistant at the University of Tokyo in 2002. Like Freenet, a user must add an encrypted node list in order to connect to other nodes on the network. Users choose three cluster words which symbolize their interests, and then Winny connects to other nodes which share these cluster words, downloading and storing encrypted data from cache of these neighbors in a distributed data store. If users want a particular file, they set up triggers (keywords), and Winny will download files marked by these triggers. The encryption was meant to provide anonymity, but Winny also included bulletin boards where users would announce uploads, and the IP address of posters could be discovered through these boards. While Freenet was implemented in Java, Winny was implemented as a Windows C++ application.
