Anonymity properties of two network coded gossip protocols

Abstract

This thesis documents the design and implementation of a new anonymous communications protocol, and an analysis of an existing protocol. NCGAB, proposed by Sergeev in 2013, eciently implements broadcast over unicast and requires no pre-existing infrastructure. We propose a second protocol, CHAP, which extends NCGAB and is designed to use wireless broadcast capabilities as well as wired links. We show anonymity for some information-theoretic measures under certain assumptions regarding adversaries and trac independence. Numerical results show that for some networks NCGAB fully anonymizes up to 90% of messages, with the remaining 10% having strong anonymity properties. NCGAB also improves up to 30% upon the baseline anonymity provided by a network coded gossip protocol not optimized for anonymity. We compare CHAP to NCGAB and show that CHAP is at least as anonymous as NCGAB and also exhibits interesting hierarchical separability that allows multiple anonymity protocols to operate simultaneously in dierent domains.