Security flaws in voting technology in a number of US states could taint the outcome of the 2012 election, a study concluded Wednesday, saying it was "highly likely" some systems will fail.
The report by two activist groups and the Rutgers University School of Law said that vulnerabilities could increase in some jurisdictions which allow some voters to cast ballots online, by email or fax.
The report, produced with the Common Cause Education Fund and the Verified Voting Foundation, repeated recommendations from those groups that any electronic votes have a paper backup system to allow an audit or recount.
"We need a paper ballot that we can go back to not when but if the machines crash or the Internet goes does down," said Pam Smith of the Verified Voting Foundation.
The report also highlighted concerns by technology specialists that electronic votes, either on touch-screen ballot machines or from remote locations, could be vulnerable to manipulation by hackers.
"On Election Day, November 6, the stakes will be high. A number of critical races will be very close, and some might be decided by very few votes," the report said.
"At the same time, it is highly likely that voting systems will fail in multiple places across the country. In fact, in every national election in the past decade, computerized voting systems have failed."
The report graded each of the states, and said the systems used in 20 were either "inadequate" or needed improvement. That includes 16 states which use paperless machines without a paper backup in some or all jurisdictions.
Six states were ranked "good" and 24 "generally good."
Any glitches could affect local races as well as the presidential race if the vote is close in key swing states.
"You can see which states could potentially pose the most difficulty if the margins are razor thin," Smith said.
The move comes with US election officials trying to upgrade technology, in some cases seeking to allow overseas and military voters to cast ballots remotely.
At the same time, officials hope to avoid a repeat of the 2000 election fiasco when the presidential vote was tainted by Florida punch card ballots with "hanging chads" that made them difficult to interpret.
Susannah Goodman of Common Cause said there have been some "positive trends" in election security in recent years but that some elections officials are overlooking cybersecurity threats that could affect online votes.
Explore further: New study will help researchers change face of military training