I'm not seeing how the verification process of making sure someone is "flesh and blood" behind their mobile app would be appreciably different than registering for a passport, for instance. A person would presumably have multiple levels of identification (state id, ssn, birth certificate) that they can send in electronically to register an account, that is then tied to a username/password/device. A "vote" would need a checkout of not only an existing account but also a new, untampered photo of your face with a piece of id, just like a real-life vote would work.