That is why there are organizations such as “True The Vote” who work to fight and prevent voter fraud.
The only way I would feel secure about the vote is an immediate and universal change to paper ballots placed in boxes. Fraud is still possible, of course, with that but the fraud has to take place at each polling place or each counting station and can be monitored to some extent. Digital voting requires a much smaller number of operatives and is not limited to corrupt precincts.