A Javascript Voting Client for Remote Online Voting.

Remote electronic voting systems enable elections where voters can vote remotely without geographical constraints using their own devices, e.g. smartphones, PCs or other Internet connected devices. Online voting systems have a set of security requirements focused on ensuring at least the same properties of traditional voting scenarios. Specifically, in Scytl's systems we provide end to end security, which guarantees that a vote is protected from the very beginning when it is generated in the voter's device until the end of the election when it is decrypted. This requires a specific software in the voters' devices, referred to as the voting client, in charge of performing most of the cryptographic operations required to protect the ballot. Our first voting clients were developed as Java Applets. However, in 2013 Scytl decided it was imperative to develop a voting client purely based on Javascript, due to the better multi-platform user experience that this web technology offers and due to the increasing loss of Java support in the browsers. This industrial paper describes the initial design challenges of the Javascript voting client, the implementation experience and the lessons learned during its development and deployment for our remote electronic voting systems. The paper is complemented with (1) an analysis of the implemented Pseudo-Random Number Generator, (2) a performance study of the main cryptographic primitives used in our voting clients and (3) a performance study of the voting casting process for a given election setup.