LAS VEGAS — After scrapping a pair of apps similar to the one that caused chaos in Iowa, the Nevada State Democratic Party said it would use paper ballots and an online check-in process in its presidential caucuses, a plan unlikely to end growing concerns about the coming vote.

In a memo distributed to representatives of the 2020 campaigns on Monday night, party officials outlined several new procedures for early caucusing, set to begin Saturday.

Among them was the use of an online Google check-in form designed to help party officials “track participants and streamline data collection” and the assignment of a numeric “voter PIN” and separate identification number tied to state voter registration to help route a participant’s ballot to their home precinct.

The plan comes a week after Nevada Democrats were forced to rip up their caucus plans in the aftermath of Iowa’s disastrous caucus result. The party had been set to use two specially designed apps developed by political technology firm Shadow, the same company that designed the vote-recording app blamed for reporting issues in Iowa.

But experts warned that this new proposal would leave the caucuses vulnerable to big security threats. They said, too, that they were puzzled by how the plan would work.

Under the original plan, Democrats could go to any early voting site, even outside the precincts where they are registered to vote, and rank their top three presidential choices on an iPad-based application. The plan was for that data to be transmitted to a voter’s home precinct for the Feb. 22 in-person caucuses.

The local caucus leader, using a second reporting app, would have incorporated their choice into the first alignment and reallocated them if their first choice proved not to be viable. The second app would have transmitted the final results to the state party.

As Iowa fell into turmoil, Nevada Democrats quickly announced they would no longer use the Shadow-designed apps and said they were looking to other vendors, to soothe concerns from local and national Democrats. By Thursday, a little over a week before early voting was set to begin, state Democrats announced they had scrapped the apps altogether.

Over the weekend, party officials were reportedly developing an iPad-based “tool,” which they insisted was not an app, to help track data from early voting. It was not immediately clear if the Google check-in form outlined in the Monday night memo was the tool that had been tested. A state party official did not respond to a request for comment.

Several campaigns declined to comment as they tried to decipher the latest developments. Multiple campaign officials have complained about a lack of transparency from the party. Though there have been multiple conference calls in the past week between the state party and the campaigns, several Democrats said party officials had been “tight-lipped” and slow to offer specific information about how the state’s ambitious early-voting plan would work without the use of the apps.

They have also questioned whether the state party is equipped to secure and handle the data from the more than 2,000 caucus sites across Nevada and avoid the kind of chaos that erupted when Iowa Democrats were forced to call in their results from all over the state. Democrats involved in the process expect about 90,000 people to caucus; they expect more than half of this year’s caucus-goers to vote early. The state party is not making a projection.

In Monday’s memo, Alana Mounce, the party’s executive director, sought to alleviate some of those concerns. She said early voting participants would be asked to fill out a “voter card” featuring the pre-generated PIN and the identification number from their registration on file with the Nevada secretary of state, which would help route the ballot to their home precincts. Voters would write down their presidential preferences on the paper ballot and then insert that into a ballot box monitored by volunteers that have received “robust training,” she said.

At the end of each day, the ballot box would be transported to “designated ballot processing hubs monitored by the state party where ballots will be scanned … and securely stored,” Mounce wrote, adding there would be a “clear chain of custody” documented on the box for security reasons.

“We’ve simplified the voting process and built in additional redundancies to streamline information and ensure we minimize errors,” Mounce wrote.

Experts said they were puzzled by the advisory from the state party.

It was unclear how rapidly voter registration information inputted on the iPads would be transmitted to the state in preparation for the general election, said David Jefferson, a computer scientist at the Lawrence Livermore National Laboratory.

The Internet hook-up involved in that transmission — and generally required for use of Google Forms — makes the process vulnerable to what’s called a denial-of-service attack, said Dan Wallach, who runs Rice University’s computer security lab. Such an attack occurs when hackers direct a stream of Internet traffic to the servers supporting the set-up, causing a crash.

Wallach said he was less concerned about voter registration systems than the actual expression of voter preferences, but said the risk was present nonetheless.

While voting itself would be analog for the early caucuses period, Jefferson said the details of the scanning system for ballots was unclear.

“It could just create an electronic image of the ballot and do nothing else, but it could also interpret the ballot and keep a running total of who cast preferences for which candidate,” Jefferson said. “It’s not clear from the state party’s instructions which it is.”