# 2-Server PIR with Sub-Polynomial Communication

@article{Dvir20142ServerPW, title={2-Server PIR with Sub-Polynomial Communication}, author={Zeev Dvir and Sivakanth Gopi}, journal={Proceedings of the forty-seventh annual ACM symposium on Theory of Computing}, year={2014} }

A 2-server Private Information Retrieval (PIR) scheme allows a user to retrieve the ith bit of an n-bit database replicated among two non-communicating servers, while not revealing any information about i to either server. In this work we construct a 2-server PIR scheme with total communication cost nO√(log log n)/(log n). This improves over current 2-server protocols which all require Ω(n1/3) communication. Our construction circumvents the n1/3 barrier of Razborov and Yekhanin which holds for…

## 66 Citations

Private Information Retrieval From Transversal Designs

- Computer ScienceIEEE Transactions on Information Theory
- 2019

This paper shows that a specific encoding of the database yields PIR protocols with reasonable communication complexity, low storage overhead, and optimal computational complexity for the servers.

Codes for distributed PIR with low storage overhead

- Computer Science2015 IEEE International Symposium on Information Theory (ISIT)
- 2015

It is proved that all known k-server PIR protocols can be efficiently emulated, while preserving both privacy and communication complexity but significantly reducing the storage overhead, and a new kind of binary linear codes are introduced, called here k- server PIR codes.

Report on PIR with Low Storage Overhead

- Computer Science
- 2015

The Fazeli, Vardy and Yaakobi paper showed that the storage overhead of a k-server PIR protocol can be arbitrarily close to the optimal value of 1 without sacrificing its communication complexity.

PIR with Low Storage Overhead: Coding instead of Replication

- Computer ScienceArXiv
- 2015

It is proved that all known information-theoretic PIR protocols can be efficiently emulated, while preserving both privacy and communication complexity but significantly reducing the storage overhead.

Building Capacity-Achieving PIR Schemes with Optimal Sub-Packetization over Small Fields

- Computer Science2018 IEEE International Symposium on Information Theory (ISIT)
- 2018

A linear capacity-achieving T-PIR scheme with sub-packetization $dn^{M-1}$ over a finite field $\mathbb{F}_{q}, q\geq N$.

Asymptotically Tight Bounds for Composing ORAM with PIR

- Computer Science, MathematicsPublic Key Cryptography
- 2017

This paper achieves a sub-logarithmic bandwidth blowup of \(O(\log _{d} N)\) (where d is a free parameter) without using expensive computation by using a d-ary tree and a two server private information retrieval (PIR) protocol based on inexpensive XOR operations at the servers.

On Computational Shortcuts for Information-Theoretic PIR

- Computer ScienceIACR Cryptol. ePrint Arch.
- 2020

The possibility of bypassing this limitation in the case where the database is a truth table of a “simple” function, such as a union of (multi-dimensional) intervals or convex shapes, a decision tree, or a DNF formula is studied.

Polynomial Batch Codes for Efficient IT-PIR

- Computer ScienceProc. Priv. Enhancing Technol.
- 2016

New “batch coding” techniques are proposed to help address PIR’s efficiency problem, and are highly tuneable, providing a means to trade off lower server-side computation cost, lower Server-side storage cost, and/or lower bi-directional communication cost in exchange for a comparatively modest decrease in resilience to Byzantine database servers.

On Quantum Advantage in Information Theoretic Single-Server PIR

- Computer ScienceIACR Cryptol. ePrint Arch.
- 2019

In (single-server) Private Information Retrieval (PIR), a server holds a large database of size n, and a client holds an index \(i \in [n]\) and wishes to retrieve i without revealing i to the server.

Henry Polynomial Batch Codes for Efficient IT-PIR

- Computer Science
- 2016

New “batch coding” techniques are proposed to help address PIR’s efficiency problem, and are highly tuneable, providing a means to trade off lower server-side computation cost, lowerServer-side storage cost, and/or lower unior bi-directional communication cost, in exchange for a comparatively modest decrease in resilience to Byzantine database servers.

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