Thanks to high transmission rates, it is now possible to download data quickly and easily from the Internet. The worldwide web offers new possibilities for exchanging data, whether in the field of art, news or science. At the same time, the Internet facilitates attacks on copyright, especially via file-sharing networks. These exchanges (called “peer-to-peer” or P2P) allow users to exchange data in any format (music files, movies, software, images, texts); these data are stored on the respective computer and the exchange is free, on a large scale and without loss of quality.