Recently, highly publicised cases of sensitive file uploading have come to light in Japan's media.
In particular, a defense agency was forced to admit that classified information from the Maritime Self Defense Force was uploaded by a computer with Winny software installed on it.
Kaneko originally anonymously announced his intent of developing the software on the Download Software board of the popular 2channel (2ch for short) Japanese bulletin board site.
Finally, they confirmed that they could indeed download the copyrighted file from the user who stated (on his thread) that he was sharing it.
Winny (also known as Win NY) is a Japanese peer-to-peer (P2P) file-sharing program which claims to be loosely inspired by the design principles behind the Freenet network, which makes user identities untraceable.
While Freenet was implemented in Java, Winny was implemented as a Windows C application.
That information includes governmental documents, information about customers, and people's private files.
Once the information is uploaded, it is difficult to delete.