OC-ORAM: Constant Bandwidth ORAM with Smaller Block Size using Oblivious Clear Algorithm

Linru Zhang, Gongxian Zeng, Yuechen Chen, Nairen Cao, Siu-Ming Yiu, Zheli Liu

2019

Abstract

Oblivious RAM has been studied extensively. A recent direction is to allow the server to perform computations instead of being a storage device only. This model substantially reduces the communication between the server and the client, making constant bandwidth communication (the number of blocks transmitted) feasible. It is obvious that the larger the block size, the easier it is to construct a constant bandwidth ORAM scheme. Also, a lower bound of sub-logarithmic bandwidth was given if we do not use expensive homomorphic multiplications. The question of “whether constant bandwidth with smaller block size without homomorphic multiplications is achievable” remains open. In this paper, we show that the block can be further reduced to O(log3N) using only additive homomorphic operations. Technically, we design a non-trivial oblivious clear algorithm with very small bandwidth to improve the eviction algorithm in ORAM for which the lower bound proof does not apply. As an additional benefit, we are able to reduce the server storage due to the reduction in bucket size.

Paper Citation

in Harvard Style

Zhang L., Zeng G., Chen Y., Cao N., Yiu S. and Liu Z. (2019). OC-ORAM: Constant Bandwidth ORAM with Smaller Block Size using Oblivious Clear Algorithm.In Proceedings of the 16th International Joint Conference on e-Business and Telecommunications - Volume 2: SECRYPT, ISBN 978-989-758-378-0, pages 149-160. DOI: 10.5220/0007924701490160

in Bibtex Style

@conference{secrypt19,
author={Linru Zhang and Gongxian Zeng and Yuechen Chen and Nairen Cao and Siu-Ming Yiu and Zheli Liu},
title={OC-ORAM: Constant Bandwidth ORAM with Smaller Block Size using Oblivious Clear Algorithm},
booktitle={Proceedings of the 16th International Joint Conference on e-Business and Telecommunications - Volume 2: SECRYPT,},
year={2019},
pages={149-160},
publisher={SciTePress},
organization={INSTICC},
doi={10.5220/0007924701490160},
isbn={978-989-758-378-0},
}

in EndNote Style

TY - CONF

JO - Proceedings of the 16th International Joint Conference on e-Business and Telecommunications - Volume 2: SECRYPT,
TI - OC-ORAM: Constant Bandwidth ORAM with Smaller Block Size using Oblivious Clear Algorithm
SN - 978-989-758-378-0
AU - Zhang L.
AU - Zeng G.
AU - Chen Y.
AU - Cao N.
AU - Yiu S.
AU - Liu Z.
PY - 2019
SP - 149
EP - 160
DO - 10.5220/0007924701490160