Robustness of interdependent networks under targeted attack

TL;DR

This paper investigates how interdependent networks respond to targeted attacks on high or low degree nodes, revealing that such networks are more vulnerable than single networks and challenging existing defense strategies.

Contribution

It introduces a general technique to analyze targeted attacks in interdependent networks by mapping them to random attacks in a transformed network pair.

Findings

Interdependent scale-free networks are more vulnerable to targeted attacks than single networks.

Protecting high-degree nodes does not significantly improve robustness of interdependent networks.

Interdependent networks have a non-zero percolation threshold under targeted attack, unlike single scale-free networks.

Abstract

When an initial failure of nodes occurs in interdependent networks, a cascade of failure between the networks occurs. Earlier studies focused on random initial failures. Here we study the robustness of interdependent networks under targeted attack on high or low degree nodes. We introduce a general technique and show that the {\it targeted-attack} problem in interdependent networks can be mapped to the {\it random-attack} problem in a transformed pair of interdependent networks. We find that when the highly connected nodes are protected and have lower probability to fail, in contrast to single scale free (SF) networks where the percolation threshold $p_c=0$, coupled SF networks are significantly more vulnerable with $p_c$ significantly larger than zero. The result implies that interdependent networks are difficult to defend by strategies such as protecting the high degree nodes that have been found useful to significantly improve robustness of single networks.