Mitigating Intersection Attacks in Anonymous Microblogging

TL;DR

This paper introduces a protocol to reduce intersection attacks in anonymous microblogging by grouping users into sets based on behavior, balancing privacy with communication efficiency, and validated on real-world data.

Contribution

The paper presents a novel protocol that mitigates intersection attacks by forming user groups and managing communication schedules, improving privacy with low bandwidth overhead.

Findings

Effective protection against intersection attacks demonstrated

Low bandwidth overhead achieved in simulations

Anonymity set size degrades slowly under churn

Abstract

Anonymous microblogging systems are known to be vulnerable to intersection attacks due to network churn. An adversary that monitors all communications can leverage the churn to learn who is publishing what with increasing confidence over time. In this paper, we propose a protocol for mitigating intersection attacks in anonymous microblogging systems by grouping users into anonymity sets based on similarities in their publishing behavior. The protocol provides a configurable communication schedule for users in each set to manage the inevitable trade-off between latency and bandwidth overhead. In our evaluation, we use real-world datasets from two popular microblogging platforms, Twitter and Reddit, to simulate user publishing behavior. The results demonstrate that the protocol can protect users against intersection attacks at low bandwidth overhead when the users adhere to communication schedules. In addition, the protocol can sustain a slow degradation in the size of the anonymity set over time under various churn rates.