FireSpam: Spam Resilient Gossiping in the BAR Model

Gossip protocols are an efficient and reliable way to disseminate information. These protocols have nevertheless a drawback: they are unable to limit the dissemination of spam messages. Indeed, messages are redundantly disseminated in the network and it is enough that a small subset of nodes forward spam messages to have them received by a majority of nodes. In this paper, we present FireSpam, a gossiping protocol that is able to limit spam dissemination. FireSpam organizes nodes in a ladder topology, where nodes highly capable of filtering spam are at the top of the ladder, whereas nodes with a low spam filtering capability are at the bottom of the ladder. Messages are disseminated from the bottom of the ladder to its top. The ladder does thus act as a progressive spam filter. In order to make it usable in practice, we designed FireSpam in the BAR model. This model takes into account selfish and malicious behaviors. We evaluate FireSpam using simulations. We show that it drastically limits the dissemination of spam messages, while still ensuring reliable dissemination of good messages.