A secure and optimally efficient multi‐authority election scheme

Abstract

Abstract. In this paper we present a new multi-authority secret-ballot election scheme that guarantees privacy, universal verifiability, and robustness. It is the first scheme for which the performance is optimal in the sense that time and communication complexity is minimal both for the individual voters and the authorities. An interesting property of the scheme is that the time and communication complexity for the voter is independent of the number of authorities. A voter simply posts a single encrypted message accompanied by a compact proof that it contains a valid vote. Our result is complementary to the result by Cramer, Franklin, Schoenmakers, and Yung in the sense that in their scheme the work for voters is linear in the number of authorities but can be instantiated to yield information-theoretic privacy, while in our scheme the voter's effort is independent of the number of authorities but always provides computational privacy-protection. We will also point out that the majority of proposed voting schemes provide computational privacy only (often without even considering the lack of information-theoretic privacy), and that our new scheme is by far superior to those schemes.

On Some Incompatible Properties of Voting Schemes

“…On the other hand, schemes using mix-nets [1, 9-12, 14, 19, 22] and/or homomorphic encryption [3,6,7] may provide it.…”

“…In voting schemes based on homomorphic encryption [3,6,7] privacy relies on computational assumptions, and is thus not unconditional. When mix-nets are used, this is the same, since the latter applies on asymmetric encryptions of the votes.…”

A Practical and Secure Coercion-Resistant Scheme for Internet Voting

“…In order to decrypt a ciphertext, a minimal number of t out n parties is necessary. See Cramer et al [9] for a description of an El Gamal threshold cryptosystem and Gennaro et al [13] for a secure key generation protocol.…”

VeryVote: A Voter Verifiable Code Voting System

“…There are techniques to verify that the ballot is well formed but they are outside the scope of this paper (e.g. Neff in [5] suggests the use of techniques presented in [15,16]). …”

“…Public Bulletin Board -To enable public verification of the election's integrity all non private data should be public, for which we use the usual public bulletin board construction [13,16]. All data in the bulletin board is authenticated by means of digital signatures.…”