COSIC seminar "Traffic Analysis by Adversaries with Partial Visibility (Iness Ben Guirat)

COSIC seminar - Traffic Analysis by Adversaries with Partial Visibility - Iness Ben Guirat (KU Leuven)
Mixnets are a fundamental privacy enhancing technology in the context of anonymous communication that have been extensively studied in terms of a Global passive Adversary (GPA). However a more realistic adversary that captures only a portion of the network have not yet been studied. We call these adversaries “Adversaries with Partial Visibility (APV)”
In this work we provide a framework that models the mixnet-based system and captures different types of Adversaries with Partial Visibility. Each adversary is modeled based on their goals, prior knowledge, and capabilities. We then use this model to perform traffic analysis using the Metropolis-Hastings algorithm in conjunction with a Bayesian inference engine. This is the first time such an adversary is explicitly defined and studied, despite this adversary model being championed as more realistic than global passive adversaries in prior work.