New Jersey's decision to allow voters displaced by superstorm Sandy to cast ballots by email has prompted a flood of warnings over security, secrecy and a potential for legal entanglements.

State officials in New Jersey announced the plan Saturday, saying it could help victims of the unprecedented storm along with rescuers who may also be unable to get to polling places.

The northeast state is allowing voters to request a ballot by e-mail or fax to their county clerk, and returning their ballot by the same means by 8:00 pm Tuesday.

Lieutenant Governor Kim Guadagno said the move was designed "to help alleviate pressure on polling places."

But some experts say email voting, which is being allowed by some states for military and overseas voters, has not been tested on a large scale and opens up a host of technical and legal obstacles.

Email ballots could be vulnerable to hacking or computer viruses, and could put the election at risk, says Matt Blaze, a University of Pennsylvania computer scientist specializing in security.

"The security implications of voting by email are, under normal conditions, more than sufficient to make any computer security specialist recoil in horror," Blaze said in a blog post.

"Email, of course, is not at all authenticated, reliable, or confidential, and that by itself opens the door to new forms of election mischief that would be far more difficult in a traditional in-person polling station or with paper absentee ballot."

But Blaze said that due to the exceptional circumstances, "the question is whether these risks outweigh the benefits, and whether the technical and procedural safeguards that are in place are adequate."

"All of this is relatively uncharted territory," Blaze added.

Andrew Appel, a Princeton University computer scientist, said that "Internet voting is inherently insecure" and that "email is the most insecure form of Internet voting."

Appel said voters emails "can be modified or interfered with without their knowledge," and that in this case "voters have to waive their right to a secret ballot."

Penny Venetis, a Rutgers University law professor, said some activists have been urging the state to require the same backup used for overseas or military voters -- paper ballots mailed in to be compared with the electronic ballot.

If this is required, Venetis said, it would mean the email vote is "unnecessary" because the vote would only be counted when a paper ballot is received.

Venetis said that without the paper requirement, "votes will be made insecure and we believe challengeable."

Pam Smith of the Verified Voting Foundation, which has long opposed electronic voting without paper backup, said a better solution for New Jersey residents would be to advise them of their right to vote at any polling place which is open.

"You can vote at any polling place in New Jersey and you won't lose privacy," she said.

Doug Kellner, co-chair, of the New York State Board of Elections, said his state opted against email voting because of "a consensus among senior election officials" that this would be "completely insecure."

But Richard Soudriette, a former election monitor who heads the Colorado-based Center for Diplomacy and Democracy, praised New Jersey for "a very ingenious solution to an almost impossible problem."

Soudriette said email voting "wouldn't pass the test under normal circumstances, but obviously this is an abnormal circumstance and given the challenges they have, it makes sense."

Soudriette said New Jersey's experience needs to be studied, but said if it works, "it could move the United States forward in terms of acceptance of Internet voting."