2-Server PIR with sub-polynomial communication

Zeev Dvir; Sivakanth Gopi

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arXiv · 1407.6692

2-Server PIR with sub-polynomial communication

Zeev Dvir·Sivakanth Gopi

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Abstract

A 2-server Private Information Retrieval (PIR) scheme allows a user to retrieve the $i$th bit of an $n$-bit database replicated among two servers (which do not communicate) while not revealing any information about $i$ to either server. In this work we construct a 1-round 2-server PIR with total communication cost $n^{O({\sqrt{\log\log n/\log n}})}$. This improves over the currently known 2-server protocols which require $O(n^{1/3})$ communication and matches the communication cost of known 3-server PIR schemes. Our improvement comes from reducing the number of servers in existing protocols, based on Matching Vector Codes, from 3 or 4 servers to 2. This is achieved by viewing these protocols in an algebraic way (using polynomial interpolation) and extending them using partial derivatives.

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BibTeX RIS

Zeev Dvir, Sivakanth Gopi. 2014-07-24. 2-Server PIR with sub-polynomial communication. https://arxiv.org/abs/1407.6692

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