PrORAM: Fast O(log n) Authenticated Shares ZK ORAM

David Heath, Vladimir Kolesnikov

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

We construct a concretely efficient Zero Knowledge (ZK) Oblivious RAM (ORAM) for ZK Proof (ZKP) systems based on authenticated sharings of arithmetic values. It consumes 2 log n oblivious transfers (OTs) of length- 2 σ secrets per access of an arithmetic value, for statistical security parameter σ and array size n. This is an asymptotic and concrete improvement over previous best (concretely efficient) ZK ORAM BubbleRAM of Heath and Kolesnikov ([HK20a], CCS 2020), whose access cost is 12log2n OTs of length- 2 σ secrets. ZK ORAM is essential for proving statements that are best expressed as RAM programs, rather than Boolean or arithmetic circuits. Our construction is private-coin ZK. We integrate it with [HK20a]’s ZKP protocol and prove the resulting ZKP system secure. We implemented PrORAM in C++. Compared to state-of-the-art BubbleRAM, PrORAM is ≈ 10 × faster for arrays of size 220 of 40-bit values.

Original languageEnglish (US)
Title of host publicationAdvances in Cryptology – ASIACRYPT 2021 - 27th International Conference on the Theory and Application of Cryptology and Information Security, 2021, Proceedings, Part 4
EditorsMehdi Tibouchi, Huaxiong Wang
PublisherSpringer
Pages495-525
Number of pages31
ISBN (Print)9783030920678
DOIs
StatePublished - 2021
Externally publishedYes
Event27th International Conference on Theory and Application of Cryptology and Information Security, ASIACRYPT 2021 - Virtual, Online
Duration: Dec 6 2021Dec 10 2021

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume13093 LNCS
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349

Conference

Conference27th International Conference on Theory and Application of Cryptology and Information Security, ASIACRYPT 2021
CityVirtual, Online
Period12/6/2112/10/21

Keywords

  • Oblivious RAM
  • Zero knowledge

ASJC Scopus subject areas

  • Theoretical Computer Science
  • General Computer Science

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