Study on the countermeasures of BitTorrent fake block attack

Fake block attack is one of the most serious threats to the security and integrity of the BitTorrent network which is a very famous peer-to-peer file sharing system. Through using a mathematic model, this paper systematically analyzes the key factors to effect the result of fake block attack and gives a novel countermeasure against this security threat. Fake block attack aims to prolong the downloading time of the target file at victim peers by wasting their download bandwidths and then to significantly damage the dissemination services of the whole target resource sharing swarm. Simulation and real world experiments prove the feasibility of fake block attack. This paper gives a stochastic model of the BitTorrent system with the impact of fake block attack, and calculates the theoretical upper bound of the result of fake block attack under the given circumstances. Finally this paper gives a two Hash value based SmartHash algorithm to enhance the robustness of BitTorrent content integrity checking progress and to counter against fake block attack. The simulation result shows that this method can effectively fight the threat of this attack.