Do You Feel a Chill?: Using PIR against Chilling Effects for Censorship-resistant Publishing

Abstract

Peer-to-peer distributed hash tables (DHTs) rely on volunteers to contribute their computational resources, such as disk space and bandwidth. In order to incentivize these node operators of privacy-preserving DHTs, it is important to prevent exposing them to the data that is stored on the DHT and/or queried for. Vasserman et al.'s CROPS aimed at providing plausible deniability to server nodes by encrypting stored content. However, node operators are still exposed to the contents of queries. We provide an architecture that uses information-theoretic private information retrieval to efficiently render a server node incapable of determining what content was retrieved in a given request by a user. We simulate our system and show that it has a small communication and performance overhead over other systems without this privacy guarantee, and significantly smaller overheads than the closest related work.