Private Information Retrieval with Sublinear Online Time

Thu 30Jan2020

Henry Corrigan-Gibbs, EPFL

From 12.00 until 13.30

At CNB/F/110 (Lunch) + CAB/F/100.9 (Seminar), ETH Zurich

Universitätstrasse 6, 8092 Zurich

Abstract:

We present the first protocols for private information retrieval that allow fast (sublinear-time) database lookups without increasing the server-side storage requirements. To achieve these efficiency goals, our protocols work in an offline/online model. In an offline phase, which takes place before the client has decided which database bit it wants to read, the client fetches a short string from the servers. In a subsequent online phase, the client can privately retrieve its desired bit of the database by making a second query to the servers. By pushing the bulk of the server side computation into the offline phase (which is independent of the client's query), our protocols allow the online phase to complete very quickly -- in time sublinear in the size of the database. Finally, we prove that our protocols are optimal in terms of the trade-off they achieve between communication and running time.

This talk will be based on joint work with Dmitry Kogan (Stanford).

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