Blocking Underhand Attacks by Hidden Coalitions (Extended Version)

TL;DR

This paper introduces deterministic and non-deterministic methods to detect and block potentially malicious agents involved in hidden coalitions within multi-agent systems, aiming to prevent underhand attacks.

Contribution

It presents the first approach to identify and block hidden coalitions in multi-agent systems, including methods with proven soundness, completeness, and computational analysis.

Findings

Deterministic method effectively blocks dangerous agents.

Non-deterministic method minimizes blocking of agents.

Both methods are computationally feasible and theoretically sound.

Abstract

Similar to what happens between humans in the real world, in open multi-agent systems distributed over the Internet, such as online social networks or wiki technologies, agents often form coalitions by agreeing to act as a whole in order to achieve certain common goals. However, agent coalitions are not always a desirable feature of a system, as malicious or corrupt agents may collaborate in order to subvert or attack the system. In this paper, we consider the problem of hidden coalitions, whose existence and the purposes they aim to achieve are not known to the system, and which carry out so-called underhand attacks. We give a first approach to hidden coalitions by introducing a deterministic method that blocks the actions of potentially dangerous agents, i.e. possibly belonging to such coalitions. We also give a non-deterministic version of this method that blocks the smallest set of potentially dangerous agents. We calculate the computational cost of our two blocking methods, and prove their soundness and completeness.