This document reviews literature on online voting systems. It discusses the background of online voting and some of the operational aspects proposed in previous systems, such as recording voter and candidate information in a database. It then outlines some of the key criticisms of online voting, noting concerns around security, anonymity, and protection against coercion. It discusses perspectives from different academics and researchers, with some viewing online voting cautiously and others being more skeptical due to the immense challenges in designing a truly secure system. Overall, the literature review identifies gaps in previous online voting systems and outlines some of the technical and implementation challenges that need to be addressed.