According to the [Kyoto-based] High-Tech Crime Task Force, the Okayama police, and the Saga police, the Osaka-based suspect uploaded about a thousand files, including anime. The suspect admitted that he thought he would not get caught because he was using Perfect Dark.
Perfect Dark is the third generation of japanese anonymous P2P network clients, developed with the intent to fix the security flaws found in its predecessors Winny and Share, in spite of also adopting a "Secure through Obscurity" closed-source model. In 2004, Winny's developer, Isamu Kaneo, was charged 1.5 million yen for assisting in copyright infringement, but he was acquited last October. Since 2008, at least 15 people were arrested in Japan suspect of uploading copyrighted material to those "secure" networks."
We warn the reader in advance that the proof presented here depends on a clever but highly unmotivated trick. -- Howard Anton, "Elementary Linear Algebra"