Hide and Seek: Outwitting Community Detection Algorithms

TL;DR

This paper introduces NEURAL, a greedy algorithm that minimally rewires networks to hide sensitive communities from detection algorithms, enhancing privacy and revealing meta-information.

Contribution

The study formalizes community deception, proves the submodularity of the objective, and presents NEURAL as a novel, efficient method for community hiding.

Findings

NEURAL effectively deceives 6 out of 7 community detection algorithms.

It outperforms 4 state-of-the-art methods on multiple metrics.

Qualitative analysis uncovers hidden meta-information in real-world networks.

Abstract

Community affiliation of a node plays an important role in determining its contextual position in the network, which may raise privacy concerns when a sensitive node wants to hide its identity in a network. Oftentimes, a target community seeks to protect itself from adversaries so that its constituent members remain hidden inside the network. The current study focuses on hiding such sensitive communities so that the community affiliation of the targeted nodes can be concealed. This leads to the problem of community deception which investigates the avenues of minimally rewiring nodes in a network so that a given target community maximally hides from a community detection algorithm. We formalize the problem of community deception and introduce NEURAL, a novel method that greedily optimizes a node-centric objective function to determine the rewiring strategy. Theoretical settings pose a restriction on the number of strategies that can be employed to optimize the objective function, which in turn reduces the overhead of choosing the best strategy from multiple options. We also show that our objective function is submodular and monotone. When tested on both synthetic and 7 real-world networks, NEURAL is able to deceive 6 widely used community detection algorithms. We benchmark its performance with respect to 4 state-of-the-art methods on 4 evaluation metrics. Additionally, our qualitative analysis of 3 other attributed real-world networks reveals that NEURAL, quite strikingly, captures important meta-information about edges that otherwise could not be inferred by observing only their topological structures.