IACR News item: 20 May 2024
Ashrujit Ghoshal, Baitian Li, Yaohua Ma, Chenxin Dai, Elaine Shi
ePrint Report
We propose a new unified framework to construct multi-server,
information-theoretic Private Information Retrieval (PIR) schemes
that leverage global preprocesing to achieve sublinear computation per query.
Despite a couple earlier attempts, our understanding of PIR schemes
in the global preprocessing model remains limited, and so far,
we only know a few sparse points in the broad design space.
With our new unified framework, we can
generalize the results of
Beimel, Ishai, and Malkin to broader parameter regimes, thus
enabling a tradeoff between bandwidth and computation.
Specifically, for any constant $S > 1$,
we can get an $S$-server scheme whose bandwidth consumption is as small as $n^{1/(S+1) + \epsilon}$ while achieving computation in the $n^\delta$ regime for some constant $\delta \in (0, 1)$.
Moreover, we can get a scheme with polylogarithmic bandwidth and computation, requiring only polylogarithmic number of servers.
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