SoK: Mechanisms Used in Practice for Verifiable Internet Voting

Increasing demands for internet voting instigated the deployment of a multitude of systems used in practice. Within this work, we are interested in which security mechanisms are currently used by vendors to implement verifiable and secret elections.
We perform a systematic market study and review academic literature, where out of 82 candidate systems, we find 29 internet voting systems that are both in active use and claim to employ some form of verifiability. Thereof, we characterize and systematize the 18 systems that provide sufficient information to extract their security mechanisms relevant for state-of-the-art verifiability and secrecy. Overall, we find that only eight systems are well-documented, of which only a few employ state-of-the-art mechanisms in all categories that we consider.