The technology already exists. It is just a matter of governments implementing the system and ensuring the robustness against fraud. Furthermore, even if not 100% of any given population subscribe to a service that would allow them to cast a vote a transitional system with traditional methods may still be required, but that would be an infinitesimal minority if compared to the overall numbers. That also brings the advantage of engaging the young generation back into politics.

Therefore, I believe this is a system that would demand some investment in the implementation phase but which would be set off by the enormous savings in the complex logistics involved in the election process, especially of countries like US and Brazil.