Dubbed "Winny", the file-sharing application is one of the most widely-used in Japan, thanks largely to a feature which allows users to remain anonymous by encrypting the data that is exchanged.
Authorities from Japan's Kyoto prefecture yesterday revealed they have detained Isamu Kaneko, the writer of Winny, for developing applications which aids copyright infringement. Kaneko teaches software development at the University of Tokyo, local police said.
Last September, the Kyoto police arrested two users who swapped movies and video games using the Winny program. This led authorities onto the trail of Kaneko, who developed and distributed the P2P tool under the nickname of "Mr. 47".
CNET Japan's Yumi Hayatsu reported from Tokyo.