Deep Root is one of three data firms hired by the Republican National Committee in the run-up to the 2016 presidential election. Founded by Alex Lundry, a data scientist on the Jeb Bush and Mitt Romney campaigns, the firm was one of three analytics teams that worked on the Trump campaign following the party’s national convention in the summer of 2016. UpGuard cyber risk analyst Chris Vickery discovered Deep Root’s data online last week. More than a terabyte was stored on the cloud server without the protection of a password and could be accessed by anyone who found the URL. Many of the files did not originate at Deep Root, but are instead the aggregate of outside data firms and Republican super PACs, shedding light onto the increasingly advanced data ecosystem that helped propel President Donald Trump’s slim margins in key swing states. Although files possessed by Deep Root would be typical in any campaign, Republican or Democratic, experts say its exposure in a single open database raises significant privacy concerns. The RNC paid Deep Root $983,000 last year, according to Federal Election Commission reports, but its server contained records from a variety of other conservative sources paid millions more, including The Data Trust (also known as GOP Data Trust), the Republican party’s primary voter file provider. Data Trust received over $6.7 million from the RNC during the 2016 cycle, according to OpenSecrets.org, and its president, Johnny DeStefano, now serves as Trump’s director of presidential personnel. The Koch brothers’ political group Americans for Prosperity, which had a data-swapping agreement with Data Trust during the 2016 election cycle, contributed heavily to the exposed files, as did the market research firm TargetPoint, whose co-founder previously served as director of Mitt Romney’s strategy team. (The Koch brothers also subsidized a data company known as i360, which began exchanging voter files with Data Trust in 2014.) Furthermore, the files provided by Rove’s American Crossroads contain strategic voter data used to target, among others, disaffected Democrats and undecideds in Nevada, New Hampshire, Ohio, and other key battleground states. Deep Root further obtained hundreds of files (at least) from The Kantar Group, a leading media and market research company with offices in New York, Beijing, Moscow, and more than a hundred other cities on six continents. Each file offers rich details about political ads—estimated cost, audience demographics, reach, and more—by and about figures and groups spanning the political spectrum. There are files on the Democratic Senatorial Campaign Committee, Planned Parenthood, and the American Civil Liberties Union, as well as files on every 2016 presidential candidate, Republicans included. Spreadsheets acquired from TargetPoint, which partnered with Deep Root and GOP Data Trust during the 2016 election, include the home addresses, birthdates, and party affiliations of nearly 200 million registered voters in the 2008 and 2012 presidential elections, as well as some 2016 voters.