ACE Seminar: Ibis: An Overlay Mix Network for Microblogging

Speaker: Prof. Ian Goldberg

Date/Time: 12-Feb-2015, 16:00 UTC

Venue: MPEB 1.03



Microblogging services such as Twitter are extremely popular. While they are commonly used by people who wish to reveal their names and friends to the world, some users, such as activists on the ground, may wish to be able to post without automatically revealing their identities or locations. An obvious approach is to use a low-latency anonymity system, such as Tor. However, low-latency systems fall prey to end-to-end timing attacks easily accomplished by an ISP or a government monitoring clients while also watching for posts to appear in real time on the microblogging site.

We present Ibis, a high-latency mix network designed specifically for microblogging. Ibis is an overlay network: the mix nodes can be microblogging clients that come online only sporadicly, and the intermediate encrypted messages are themselves posted as microblogged entries. We accomplish this through a novel cryptographic mix message format that uses only 47 bytes of overhead, while maintaining three-hop, 128-bit security against offline attack.

This is joint work with Paul Hendry.



Ian Goldberg is an Associate Professor of Computer Science and a University Research Chair at the University of Waterloo, where he is a founding member of the Cryptography, Security, and Privacy (CrySP) research group. His research focuses on developing usable and useful technologies to help Internet users maintain their security and privacy. He is a Senior Member of the ACM and a winner of the Electronic Frontier Foundation's Pioneer Award. He is currently on sabbatical as a Visiting Fellow at Clare Hall, University of Cambridge.

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