  Countries like Estonia, Norway or Australia developed electronic voting
systems, which could be used to realize parliamentary elections with the help
of personal computers and the Internet. These systems are completely different
in their design and their way to solve the same problem. In this thesis, we
analyze some of the largest real-world systems, describe their building blocks
and their general design to focus on possible problems in these electronic
voting systems.
  Furthermore, we present a template for an e-voting system, which we designed
to try to fulfill the preliminaries and requirements of a secure electronic
voting system. We use the experiences and the building blocks of existing
systems to combine them to another more secure system. Afterwards, we compare
our concept with real-world systems to evaluate the fulfillments of the
requirements. Conclusively, we discuss the occurring problems when designing a
secure system.
  Peer-to-peer networks provide many advantages, like decentralization, which
might be applicable to electronic voting systems. Therefore, we take a look on
the distributed database called blockchain and the usage in a peer-to-peer
voting system. Our contribution to this topic is a modification of the
proof-of-stake, which enables the usage of common devices, like smartphones or
tablets, for the blockchain verification and inclusion of new ballots to the
chain. This proof does not need much computing power and has a lower carbon
footprint than the proof-of-work in the Bitcoin protocol.

Cryptography and Security