Know the real risks
Election fraud is not one thing. The main risks are: ineligible people voting, people voting more than once, ballots being altered or lost, the count being manipulated, and voters being coerced. A serious system has a specific defense for each, rather than a vague promise of being 'secure'.
Authentication and one person, one vote
Strong authentication against the census prevents ineligible voting, and the system enforces a single ballot per voter. Matching the strength of authentication to the stakes is part of good design.
Tamper-evidence and a verifiable count
Encrypted ballots and a tamper-evident record make it obvious if anything is altered. An end-to-end verifiable tally means manipulation of the count is not just prohibited - it is detectable by anyone, because the published proof would not check out.
Coercion resistance and open scrutiny
Genuine ballot secrecy removes the ability to buy or coerce votes, because no one can prove how they voted. And open-source code lets security researchers find and fix weaknesses in the open, which is far safer than hoping a closed system has no flaws.