Cryptology ePrint Archive: Report 2017/098

Designing Fully Secure Protocols for Secure Two-Party Computation of Constant-Domain Functions

Vanesa Daza and Nikolaos Makriyannis

Abstract: In a sense, a two-party protocol achieves fairness if the output from the computation is obtained simultaneously by both parties. A seminal result by Cleve (STOC 1986) states that fairness is impossible, in general. Surprisingly, Gordon et al.~(JACM 2011) showed that there exist interesting functions that are computable with fairness. The two results give rise to a distinction between \emph{fair} functions and \emph{unfair} ones. The question of characterizing these functions has been studied in a sequence of works leading to the complete characterization of (symmetric) Boolean functions by Asharov et al.~(TCC 2015). In this paper, we propose a generic construction of a fully secure (fair) protocol, starting with a constant-round protocol satisfying limited security requirements. Our results introduce new conceptual tools for the analysis of fairness and they apply to arbitrary (constant-domain) functions. As a case study, we consider asymmetric Boolean functions. While the characterization remains open, we believe that our results lay the foundation for a deeper understanding of fairness.

Category / Keywords: cryptographic protocols / Fairness, Secure Two-Party Computation, Malicious Adversaries, Cryptographic Protocols

Date: received 8 Feb 2017

Contact author: n makriyannis at gmail com

Available format(s): PDF | BibTeX Citation

Version: 20170213:193503 (All versions of this report)

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