Cryptology ePrint Archive: Report 2014/706

The Feasibility of Outsourced Database Search in the Plain Model

Carmit Hazay and Hila Zarosim

Abstract: The problem of securely outsourcing computation to an untrusted server gained momentum with the recent penetration of cloud computing services. The ultimate goal in this setting is to design efficient protocols that minimize the computational overhead of the clients and instead rely on the extended resources of the server. In this paper, we focus on the outsourced database search problem which is highly motivated in the context of delegatable computing since it offers storage alternatives for massive databases, that may contain confidential data. This functionality is described in two phases: (1) setup phase and (2) query phase. The main goal is to minimize the parties workload in the query phase so that it is proportional to the query size and its corresponding response.

In this work we study whether a trusted setup or a random oracle are necessary for protocols with minimal interaction that meet the optimal communication and computation bounds in the query phase. We answer this question positively and demonstrate a lower bound on the communication or the computational overhead in this phase. We further abstract the security properties of the underlying cryptographic primitive that imply private outsourced database search with minimal interaction. For a large class of search functionalities the communication complexity of our protocol meets our lower bound.

Category / Keywords: cryptographic protocols / Outsourced Computation, Database Search Functionalities, Lower Bound, Communication and Computational Complexities, Minimal Interaction

Date: received 8 Sep 2014, last revised 22 Feb 2015

Contact author: carmit hazay at biu ac il

Available format(s): PDF | BibTeX Citation

Version: 20150222:070111 (All versions of this report)

Short URL: ia.cr/2014/706

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