PriFi

PriFi [1] is an anonymous communication network, developped at the EPFL and Yale University. It protects your privacy by preventing your employers, ISPs and the governements from tracking what you are doing on the Internet; more precisely, it hides the source of your communications. Conceptually close to Tor [2], PriFi aims to provide lower latency and better anonymity, and is tailored for WLANs and LANs.

Get PriFi : github.com/lbarman/prifibuild statusgo report cardCoverage Status

PriFi is under active development; feel free to contact us if you want to contribute !

PriFi around the world

[graphic only visible when we will have statistics to show

What PriFi provides

How it works

PriFi is build upon Dining Cryptographer Networks [3], a cryptographic primitive that provides perfect anonymity.1 It is tailored for WLANs and LANs, hence it works best at your company, university campus, or in your home. PriFi works like a trustless VPN : install it on the computers of your users, and it anonymizes any kind of traffic transparently.

PriFi uses a client-server infrastructure for performance and security. It relies mostly on existing infrastructure : a relay/router, a set of clients, and some additional servers. Those public servers, located anywhere on the planet, are not fully trusted; to be precise, they are in the anytrust model [4].

PriFi architecture
Figure 1 : PriFi architecture relies on existing relay/clients, and requires additional public servers.

Those servers provide security; the first interesting property is the anytrust model, which means that as long as any one of the selected server is honest, PriFi will keep its security guarantees. In practice, your organization can select a set of server it trusts; those servers can get compromized, as long as not all of them are compromized, PriFi delivers strong anonymity.

The second interesting property is the path taken by the data; unlike Tor and other mixnets, the anonymized data does not go through the servers. This is important since the latency to those server is usually orders of magnitude above the latency in a WLAN/LAN; In PriFi, this high latency path matters only at setup. Once the setup phase is done, the packets from the clients to the Internet follow their usual path, with no added hop that would increases latency.

PriFi high- and low- latency paths
Figure 2 : Low-latency path (order of magnitude : 10ms) and high-latency path (order of magnitude : 100ms).

1 This construction provides perfect anonymity; in particular, it is resistant to traffic-analysis attacks [5], unlike Tor (and other systems). Those attacks exploit differences in traffic flows between users, and are an effective way to de-anonymize users.

Technical documents

People

Bryan Ford

Prof. Bryan Ford
EPFL

www

Joan Feigenbaum

Prof. Joan Feigenbaum
Yale

www

Jean-Pierre Hubaux

Prof. Jean-Pierre Hubaux
EPFL

www

Mahdi Zamani

Mahdi Zamani
Yale

www

Italo Dacosta

Italo Dacosta
EPFL

www

Ennan Zhai

Ennan Zhai
Yale

www

Ludovic Barman

Ludovic Barman
EPFL

www

Jayshree Sarathy

Jayshree Sarathy
Yale

Julien Weber

Julien Weber
EPFL

Matthieu Girod

Matthieu Girod
EPFL

www

git repositories

References

  1. [1] Barman, Ludovic; Zamani, Mahdi; Dacosta, Italo; Feigenbaum, Joan; Ford, Bryan; Hubaux, Jean-Pierre and Wolinsky, David. PriFi: A Low-Latency and Tracking-Resistant Protocol for Local-Area Anonymous Communication. Proceedings of the 2016 ACM on Workshop on Privacy in the Electronic Society
  2. [2] Dingledine, Roger; Mathewson, Nick and Syverson, Paul. Tor: The second-generation onion router.
  3. [3] Chaum, David. The dining cryptographers problem: Unconditional sender and recipient untraceability. Journal of cryptology
  4. [4] Wolinsky, David I; Corrigan-Gibbs, Henry; Ford, Bryan and Johnson, Aaron. Scalable anonymous group communication in the anytrust model.
  5. [5] Raymond, Jean-Fran├žois. Traffic analysis: Protocols, attacks, design issues, and open problems. Springer
  6. [6] DeDiS Lab, EPFL. Secure Distributed Algorithm. https://github.com/dedis/cothority