Some voting systems are reliant on external authentication services.
Others use cryptography to implement their own. We combine
digital signatures and non-interactive proofs to derive a generic construction
for voting systems with their own authentication mechanisms, from systems
that rely on external authentication services. We prove that our
construction produces systems satisfying ballot secrecy and election
verifiability, assuming the underlying voting system does. Moreover,
we observe that works based on similar ideas provide neither ballot secrecy nor
election verifiability. Finally, we demonstrate applicability of
our results by applying our construction to the Helios voting system