TOWARDS PRIVACY-PRESERVING AND ROBUST WEB OVERLAYS

Abstract

In this thesis, we analyze privacy and robustness issues in web overlays, and propose solutions to address these issues using cryptographic and hardware primitives. First, we present inference attacks in peer-assisted content delivery networks (CDNs) on top of web overlays, which can be used by local passive adversaries to infer user’s online activities. To thwart such attacks, we propose an anonymous peer-assisted CDN (APAC), which employs onion-routing techniques to conceal users’ identities. Second, to handle with global passive adversaries performing long-term traffic analysis, we further design an oblivious peer-to-peer content sharing system (OblivP2P), which uses new primitives such as distributed oblivious RAM (ORAM) in the P2P setting. Lastly, to ensure the robustness of protocols against byzantine adversaries, we leverage a new hardware primitive, Intel software guard extensions (SGX). By enforcing our security properties, we confine byzantine nodes to have no extra advantage than omitting messages and improve the efficiency of P2P protocols in the synchronous setting.