Can we cast a ballot as intended and be receipt free?

This paper explores the interaction between receiptfreeness and cast-as-intended verifiability, a property that has been overlooked until now or assumed to be granted through procedural means in the context of receipt-free voting protocols.

We first demonstrate that it is impossible to obtain a receipt-free voting protocol with cast-as-intended verifiability if the voting process is non-interactive, unless a trusted authority is available. We also demonstrate that, if a trusted voter registration authority is available, then cast-as-intended verifiability and receipt-freeness can be obtained.

Furthermore, after extending standard receipt-freeness security definitions to an interactive voting (and corruption) setting, we demonstrate that the same security properties can be obtained using an interactive voting process.

Finally, we discuss the performance of our protocols based on a prototype implementation.