The data — which included names, birthdays, and personal addresses — was discovered in June 2017 on an Amazon web server by the cyber risk firm UpGuard. UpGuard described the mishap as “perhaps the largest known exposure of voter information in history.”

The RNC moved swiftly to separate itself from Deep Root Analytics and the firm locked down the information to prevent further public access. Republican officials say the data was unsecured for around two weeks and that other than UpGuard no one gained access.

RNC officials said the firm has taken aggressive steps to address the past failure, such as upping its investment in cybersecurity, bolstering employee training, and updating its security measures.

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People familiar with the new arrangement say the firm's work for the committee is focused on data analytics and media-tracking projects.

“The RNC has and will continue to take the security of voter information extremely seriously. Over the past three years, Deep Root has overhauled their security protocols and maintains a robust security posture,” said Mike Reed, an RNC spokesman. “We are confident that their system is safe and secure.”

The move comes as President Donald Trump’s political operation beefs up its data infrastructure ahead of the general election. The Trump campaign has functioned largely as a digital-focused effort. Under campaign manager Brad Parscale, who served as digital director on Trump’s 2016 bid, the president’s political organization has undertaken projects such as gathering data on attendees at his rallies.

Alex Lundry, Deep Root’s co-founder, previously worked on Mitt Romney’s 2012 bid. He has specialized in the targeting of television advertising.

The RNC was not the only organization Deep Root Analytics contracted with during the 2016 election cycle. The outfit worked for Senate Leadership Fund, a super PAC closely aligned with Majority Leader Mitch McConnell, and Right to Rise, an outside group that supported former Florida Gov. Jeb Bush’s presidential campaign.

While the RNC cut ties with the Deep Root Analytics during the 2018 midterms, the firm worked for a range of party groups including the National Republican Senatorial Committee and the House GOP-aligned Congressional Leadership Fund.

This cycle, the outfit’s clients include McConnell and Maine Sen. Susan Collins, both of whom are seeking reelection.

“Since 2017, Deep Root has satisfied the security requirements of over 100 different organizations and has done work for every major center-right political entity. We have the best product in the business and are excited to be working with the RNC in this cycle,” Lundry said in a statement.

Separately, the RNC has tapped Howler Insights, LLC, a subsidiary of Deep Root Analytics, which shares office space with the firm. Party officials say Howler is at work on a data project that will play a role in the 2020 election.

According to campaign finance records, the RNC paid $900,000 to Howler in September. The disbursement was first reported by ProPublica.