Australia and other countries are a decade or longer away from safe methods of online voting in state and national elections and current tools pose a serious risk to democratic processes, people at a public lecture heard on Monday night.
University of Michigan researcher J Alex Halderman and University of Melbourne research fellow Vanessa Teague said online voting in Saturday's New South Wales election could have been seriously compromised through security weaknesses in the iVote system, being used in the upper house.
The pair, in a a public lecture at the Australian National University, said that internet voting continued to raise some of the most difficult challenges in computer security and could not be considered completely safe.
They reported faults in the NSW system to electoral authorities last week, ahead of as many as 250,000 voters using online systems to participate in the ballot.
Professor Halderman said online voting currently did not meet the expectations of voters in democratic elections.
"If you talk to almost any security expert, what you will hear is that existing technology just isn't up to the task yet," he said before the lecture.
"We need research, potentially decades of progress in security before we're going to get there. Voting online requires you to solve some of the hardest problems in computer security."
Most governments recognised the limitations of online voting security, Professor Halderman said, and the NSW election would be the largest ever online poll, despite the reported risk.
"We would have urged them not to use the iVote system, certainly not to open it up as widely as they have. You just need some very small thing to go wrong in order to compromise the integrity of the entire election."
To use the online, remote voting tool, voters must be blind or have low vision, have reading difficulties or other disabilities, live more than 20 kilometres from a polling place or be interstate or overseas on election day.
Voters must register, be provided with a special user number and an access PIN. Ballots are encrypted and randomised for counting.
Representatives of the Outdoor Recreation Party and the Animal Justice Party have pledged to appeal through the courts if the outcome is seen to be close.
Working with colleagues, Professor Halderman has previously studied online voting systems in the United States and Europe, using in-depth security evaluations. They found systems, including in Estonia, that were vulnerable to hackers, overseas governments and even dishonest local election officials.
To demonstrate the risks, the group joined a public trial of an internet voting system in Washington DC and within 48 hours had complete control of the server and changed all the votes.
An internationally recognised expert, Professor Halderman contributed to India's first independent review of the election technology used by half a billion voters.
ACT Electoral Commissioner Philip Green said last week there was no expectation of internet voting in the 2016 territory election, but some offline electronic voting measures would be adapted for the redrawn electoral boundaries.
Dr Teague described internet voting as remaining much more complicated than online banking or other e-commerce.
"The requirements to keep the votes private even from the people at the electoral commission, combined with the requirement to demonstrate in a public and verifiable way that the system got the right answer, is an incredibly high bar for an electoral system."
She said some security measures and evidence procedures at the polling place could reduce risk but not provide full confidence in the outcome.