Isamu Kaneko, 33, was arrested for suspected conspiracy to commit copyright violation by the High-tech Crime Taskforce of the Kyoto Prefectural Police, in the country's first arrest of the developer of a file-sharing application, a police spokesman said.

The alleged offense is punishable by up to three years in prison or a maximum fine of three million yen (26,700 dollars).

Kaneko, known as only "47" in cyberspace, is a research assistant in a computer-engineering graduate course at Japan's most prestigious Tokyo University.

He developed the file-sharing application, called Winny, and released it free of charge over the Internet in May 2002, enabling users to exchange files stored in their computers.

More than one million people are believed to be using Winny in Japan, according to Kyoto police.

Files designated as available for exchange by Winny users include pirated films, music, game software and other confidential information believed to have been leaked intentionally or by mistake.

The Mainichi Shimbun daily has said some 200 sorts of confidential information such as internal army documents and wages for postal workers have been circulated among Winny file sharers.

The spokesman said Kyoto police had been aware of Kaneko's activity since at least last autumn as their "cyber patrol unit" searched his apartment in November in connection with the arrest of two Winny users aged 41 and 19 for engaging in piracy.

SPACE.WIRE