Abstract: A file sharing system includes a first primary peer which shares data with other peers via a tracker. The tracker divides the data into blocks and encrypts each block of the first data with a key that is unique to the first primary peer and the respective block of data. As the encrypted blocks of data are passed from peer to peer in the file sharing system, the tracker is always able to identify the primary which provided the data. Additionally, primary peers are compensated in accordance with the number of downloads of their respective data.