Individual Security and Network Design with Malicious Nodes

TL;DR

This paper investigates how to design and defend networks against malicious, Byzantine nodes, demonstrating that decentralized defense can be as effective as centralized strategies in mitigating security risks.

Contribution

It introduces a model for network design with malicious nodes and shows decentralized defense can fully mitigate inefficiencies caused by Byzantine nodes.

Findings

Decentralized defense can match centralized defense effectiveness.

Optimal network design accounts for malicious node presence.

Decentralization does not necessarily impair security mitigation.

Abstract

Networks are beneficial to those being connected but can also be used as carriers of contagious hostile attacks. These attacks are often facilitated by exploiting corrupt network users. To protect against the attacks, users can resort to costly defense. The decentralized nature of such protection is known to be inefficient but the inefficiencies can be mitigated by a careful network design. Is network design still effective when not all users can be trusted? We propose a model of network design and defense with byzantine nodes to address this question. We study the optimal defended networks in the case of centralized defense and, for the case of decentralized defense, we show that the inefficiencies due to decentralization can be fully mitigated, despite the presence of the byzantine nodes.