Title: Outsourcing computation for private function evaluation

Authors: Henry Carter; Patrick Traynor

Addresses: Department of Computing Sciences, Villanova University, Philadelphia, PA, USA ' Department of Computer and Information Science and Engineering, University of Florida, Gainesville, FL, USA

Abstract: Outsourced secure multiparty computation (SMC) protocols allow resource-constrained devices to execute input-private computation with great efficiency. Unfortunately, existing outsourced SMC protocols require that all parties know the function being evaluated, precluding applications where the function itself must remain private. We develop the first linear-complexity protocols for outsourcing private function evaluation (PFE), SMC protocols that provide input and function privacy. Assuming a semi-honest function holder, we build on existing two-party PFE constructions to develop outsourced protocols that are secure against a semi-honest, covert, or malicious outsourcing server and malicious mobile participants. To do this, we develop a garbling technique for combining public and private sub-circuits in a single computation. This allows us to apply auxiliary checks for malicious behaviour using only free-XOR gates. These protocols demonstrate the feasibility of outsourced PFE and provide a first step towards privacy-preserving applications for use in cloud computing.

Keywords: private function evaluation; PFE; garbled circuits; server-assisted cryptography.

DOI: 10.1504/IJICS.2019.103052

International Journal of Information and Computer Security, 2019 Vol.11 No.6, pp.525 - 561

Received: 22 Sep 2016
Accepted: 12 May 2017
Published online: 15 Oct 2019 *

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