Title: Multi-writer multi-reader conjunctive keyword searchable encryption

Authors: Dhruti Sharma; Devesh C. Jinwala

Addresses: Department of Computer Engineering, Sardar Vallabhbhai National Institute of Technology, Surat, Gujarat, India ' Department of Computer Engineering, Sardar Vallabhbhai National Institute of Technology, Surat, Gujarat, India

Abstract: We explore the area of searchable encryption aiming to identify the schemes supporting multiple data owner (writers) and multiple data users (readers). Especially, we observe multi-writer multi-reader (MWMR) searchable encryption schemes focusing on multi-keyword search. However, such MWMR schemes offer a centralised token generation approach whereby an enterprise trusted authority (ETA) issues a search token to each reader in system, and thus introduce two serious issues, viz. leakage of keywords to ETA and O(q · R) communication overhead for R readers and q queries per reader. In this paper, we alleviate these issues by proposing an MWMR scheme with a decentralised token generation approach. With such an approach, a registered data reader constructs a search token without interacting with ETA and thus provides an efficient token generation with keyword privacy from ETA. Additionally, we incorporate a more expressive especially, conjunctive keyword search with the scheme. With formal security analysis, we prove that the scheme effectively stands against chosen keyword attack performed by inside or outside attacker. With theoretical and empirical analysis, we justify the effectiveness of the proposed scheme.

Keywords: searchable encryption; multi-writer multi-reader searchable encryption; MWMR; conjunctive keyword search; decentralised token generation; indistinguishability of ciphertext against chosen keyword attack; IND-CKA.

DOI: 10.1504/IJICS.2021.116303

International Journal of Information and Computer Security, 2021 Vol.15 No.2/3, pp.141 - 162

Received: 23 Feb 2018
Accepted: 25 May 2018
Published online: 20 Jul 2021 *

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