TR CCIT 500, Department of Electrical Engineering, Technion, March 2004.
An intrusion-tolerant version of a gossip-based multicast algorithm, developed by G. Badishi, I. Keidar and A. Sasson, employs several schemes in order to minimize the effect of DoS attacks on a member. One possible attack on this protocol is one in which a malicious (or a malfunctioning) process acts normally, but actually does not forward any useful messages, and replies to pull requests with null entries, thus affecting the performance of the protocol. In this project we suggest a failure detector for such a malfunction or attack and a way to overcome it.