jsun@cs.ucr.edu |
anirban@cs.ucr.edu |
michalis@cs.ucr.edu |
However, Hale and Patarin identify the weakness of TFT and hypothesize that it is possible to use multiple identities to cheat and the success of BT is due to other reasons, notably the lack of meta-data search. To test whether this hypothesis is true and also to better understand why BT systems are so successful, we modify the official BT source code to allow the creation of multiple processes by one BT client. These processes use different identities and cooperatively download the same file simultaneously. They download different pieces of the same file without overlapping using several piece selection and sharing algorithms. Experiment results show that these approaches may speed up the download process in a few selected cases. However, no approach can achieve consistent speedup under any case and simply increasing the number of processes may do more harm than help. This shows that the BT protocol is rather resilient to such exploits of using multiple identities. We argue that if such exploits were easily achievable, then BT systems would have suffered breakdown long time ago.
Here is a detailed commentary on the BitTorrent mainline client V4.0.4, which we modify to implement multiple identities in BitTorrent system.
Currently we only offer modification to the command-line interface provided by BT client. If you are also interested in trying this modified client, you can download and have a try.
Our work was accepted by IEEE/IETF Networking 2007 and a copy of this work is available upon request. It is also the base of my Master's project. Full-text of Jin Sun's thesis is available in either PDF format.