15 research outputs found
Verifiability of Helios Mixnet
We study game-based definitions of individual and universal verifiability
by Smyth, Frink & Clarkson. We prove that building voting systems
from El Gamal coupled with proofs of correct key generation
suffices for individual verifiability.
We also prove that it suffices for an aspect of universal verifiability.
Thereby eliminating the expense of individual-verifiability proofs and
simplifying universal-verifiability proofs for a class of encryption-based
voting systems. We use the definitions of individual and universal verifiability
to analyse the mixnet variant of Helios. Our analysis reveals that universal verifiability
is not satisfied by implementations using the weak Fiat-Shamir transformation.
Moreover, we prove that individual and universal verifiability are satisfied
when statements are included in hashes (i.e., when using the Fiat-Shamir
transformation, rather than the weak Fiat-Shamir transformation)