PriFi: Low-Latency Anonymity for Organizational Networks
Ludovic Barman, Italo Dacosta, Mahdi Zamani, Ennan Zhai, Apostolos Pyrgelis, Bryan Ford, Jean-Pierre Hubaux, and Joan Feigenbaum
Privacy Enhancing Technologies Symposium
July 13, 2020
Proceedings on Privacy Enhancing Technologies
Volume 2020, Issue 4.
Organizational networks are vulnerable to traffic-analysis attacks that enable
adversaries to infer sensitive information from the network traffic – even
if encryption is used. Typical anonymous communication networks are tailored to
the Internet and are poorly suited for organizational networks. We present
PriFi, an anonymous communication protocol for LANs: it protects users against
eavesdroppers and provides traffic-analysis resistance. PriFi builds on Dining
Cryptographers networks but reduces the high communication latency of prior
work via a new client/relay/server architecture, in which a client’s packets
remain on their usual network path without additional hops, and in which a set
of remote servers assist the anonymization process without adding latency. PriFi
also solves the challenge of equivocation attacks, which are not addressed by
related works, by encrypting the traffic based on the communication history.
Our evaluation shows that PriFi introduces a small latency overhead (≈ 100ms for
100 clients) and is compatible with delay-sensitive applications such as VoIP.