Nearly 140 West Virginians living abroad in 29 countries have cast their election ballots in an unprecedented pilot project that involves voting remotely by mobile device, according to state officials. The statewide pilot, which covers 24 of West Virginia's 55 counties, uses a mixture of smartphones, facial recognition and the same technology that underpins bitcoin -- the blockchain -- in an effort to create a large-scale and secure way for service members, Peace Corps volunteers or other Americans living overseas to participate in the midterm elections. West Virginia is the first state to run a blockchain-based voting project at such a scale, state officials say. And if adopted more widely, the technology could make it easier to vote and potentially reduce long lines at the polls. But many security experts worry that the technology may not be ready for broader use -- and could even contain vulnerabilities that risks the integrity of elections.