Cryptology ePrint Archive: Report 2019/822

Surveying definitions of coercion resistance

Thomas Haines and Ben Smyth

Abstract: We explore formal definitions of coercion resistance (WPES'05, FC'09, CRYPTO'10, and CSF'10), conceived to capture the strongest privacy notions achievable by voting systems. We find all but one is unsuitable, demonstrating difficulties faced by our community in formalising this property and raising questions over the security of schemes striving to deliver coercion resistance. We find the remaining definition to be reliant on burdensome combinatorial analysis, prohibiting immediate application. We propose a variant that simplifies application. We also patch an unsuitable definition and introduce sufficient conditions to simplify proofs.

Category / Keywords: cryptographic protocols / election schemes

Date: received 15 Jul 2019, last revised 31 Aug 2020

Contact author: research at bensmyth com

Available format(s): PDF | BibTeX Citation

Version: 20200831:152803 (All versions of this report)

Short URL: ia.cr/2019/822