Cryptology ePrint Archive: Report 2019/026

Non-malleable encryption with proofs of plaintext knowledge and applications to voting

Ben Smyth and Yoshikazu Hanatani

Abstract: Non-malleable asymmetric encryption schemes which prove plaintext knowledge are sufficient for secrecy in some domains. For example, ballot secrecy in voting. In these domains, some applications derive encryption schemes by coupling malleable ciphertexts with proofs of plaintext knowledge, without evidence that the sufficient condition (for secrecy) is satisfied nor an independent security proof (of secrecy). Consequently, it is unknown whether these applications satisfy desirable secrecy properties. In this article, we propose a generic construction for such a coupling and show that our construction produces non-malleable encryption schemes which prove plaintext knowledge. Furthermore, we show how our results can be used to prove ballot secrecy of voting systems. Accordingly, we facilitate the development of applications satisfying their security objectives.

Category / Keywords: foundations / anonymity, applications, election schemes, foundations, implementation, malleability, non-malleability, privacy, public-key cryptography, secrecy, zero knowledge

Date: received 10 Jan 2019

Contact author: toshiba at bensmyth com

Available format(s): PDF | BibTeX Citation

Version: 20190115:192309 (All versions of this report)

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