KarmaNET: Leveraging trusted social paths to create judicious forwarders

Many existing problems in distributed systems can be linked to routing being orthogonal to trust and ignoring the social connectivity. This paper introduces a novel and economical protocol, entitled KarmaNET, which binds any routing protocol with trust to build a trusted social path and create judicious forwarders. This creates incentives for nodes to build good karma, and excises any node that has accumulated too much bad karma. KarmaNET requires only local knowledge, cuts off malicious nodes at the source, adapts to dynamic changes in behavior, bounds the number of unwanted messages a node can generate in its lifetime (even in the presence of collusion, part-time spammers, and errors in marking the outcome), and achieves an expected 0 spams received per node in the limit. KarmaNET ostracizes spammers, freeloaders, and minimizes Sybil attacks with negligible false positive and negative rates (less than 0.5%). We theoretically prove bounds on the damage an attacker can cause, that KarmaNET achieves exponentially fast adaptation to a node´s dynamic behavior, and show that our simulation matches the theory.